diff --git a/__tests__/main.test.ts b/__tests__/main.test.ts
index ebf454c..2ba3ae5 100644
--- a/__tests__/main.test.ts
+++ b/__tests__/main.test.ts
@@ -2,11 +2,11 @@ import {wait} from '../src/wait'
 import * as process from 'process'
 import * as cp from 'child_process'
 import * as path from 'path'
-import { ReleaseNotes } from '../src/releaseNotes';
-import { readConfiguration } from '../src/utils';
-import { createCommandManager } from '../src/git-helper';
-import * as core from '@actions/core';
-import { Tags } from '../src/tags';
+import {ReleaseNotes} from '../src/releaseNotes'
+import {readConfiguration} from '../src/utils'
+import {createCommandManager} from '../src/git-helper'
+import * as core from '@actions/core'
+import {Tags} from '../src/tags'
 
 // shows how the runner will run a javascript action with env / stdout protocol
 /*
@@ -22,22 +22,21 @@ test('test runs', () => {
 })
 */
 
-it("Should be true", async () => {
-    jest.setTimeout(180000);
-    
-    const configuration = readConfiguration('configuration.json')
-    const releaseNotes = new ReleaseNotes({
-        owner: "mikepenz",
-        repo: "MaterialDrawer",
-        fromTag: null,
-        toTag: "v8.1.6",
-        configuration: configuration
-    })
-    
+it('Should be true', async () => {
+  jest.setTimeout(180000)
 
-    const changeLog = await releaseNotes.pull()
-    console.log(changeLog)
-    expect(changeLog).toStrictEqual(`
+  const configuration = readConfiguration('configuration.json')
+  const releaseNotes = new ReleaseNotes({
+    owner: 'mikepenz',
+    repo: 'MaterialDrawer',
+    fromTag: null,
+    toTag: 'v8.1.6',
+    configuration: configuration
+  })
+
+  const changeLog = await releaseNotes.pull()
+  console.log(changeLog)
+  expect(changeLog).toStrictEqual(`
 
 <details>
 <summary>Uncategorized</summary>
diff --git a/src/commits.ts b/src/commits.ts
index 6751c42..97113af 100755
--- a/src/commits.ts
+++ b/src/commits.ts
@@ -1,70 +1,92 @@
-import { Octokit, RestEndpointMethodTypes } from "@octokit/rest"
-import moment from 'moment';
-import * as core from '@actions/core';
+import moment from 'moment'
+import * as core from '@actions/core'
+import {Octokit, RestEndpointMethodTypes} from '@octokit/rest'
 
 export interface CommitInfo {
-    sha: string
-    summary: string
-    message: string
-    author: string
-    date: moment.Moment
-    prNumber: number | undefined
+  sha: string
+  summary: string
+  message: string
+  author: string
+  date: moment.Moment
+  prNumber: number | undefined
 }
 
 export class Commits {
-    constructor(private octokit: Octokit) { }
+  constructor(private octokit: Octokit) {}
 
-    async getDiff(owner: string, repo: string, base: string, head: string): Promise<CommitInfo[]> {
-        const commits: CommitInfo[] = await this.getDiffRemote(owner, repo, base, head)
-        return this.sortCommits(commits)
+  async getDiff(
+    owner: string,
+    repo: string,
+    base: string,
+    head: string
+  ): Promise<CommitInfo[]> {
+    const commits: CommitInfo[] = await this.getDiffRemote(
+      owner,
+      repo,
+      base,
+      head
+    )
+    return this.sortCommits(commits)
+  }
+
+  private async getDiffRemote(
+    owner: string,
+    repo: string,
+    base: string,
+    head: string
+  ): Promise<CommitInfo[]> {
+    // Fetch comparisons recursively until we don't find any commits
+    // This is because the GitHub API limits the number of commits returned in a single response.
+    let commits: RestEndpointMethodTypes['repos']['compareCommits']['response']['data']['commits'] = []
+    let compareHead = head
+    while (true) {
+      const compareResult = await this.octokit.repos.compareCommits({
+        owner,
+        repo,
+        base,
+        head: compareHead
+      })
+      if (compareResult.data.total_commits === 0) {
+        break
+      }
+      commits = compareResult.data.commits.concat(commits)
+      compareHead = `${commits[0].sha}^`
     }
 
-    private async getDiffRemote(owner: string, repo: string, base: string, head: string): Promise<CommitInfo[]> {
-        // Fetch comparisons recursively until we don't find any commits
-        // This is because the GitHub API limits the number of commits returned in a single response.
-        let commits: RestEndpointMethodTypes["repos"]["compareCommits"]["response"]["data"]["commits"] = []
-        let compareHead = head
-        while (true) {
-            const compareResult = await this.octokit.repos.compareCommits({ owner, repo, base, head: compareHead })
-            if (compareResult.data.total_commits === 0) {
-                break
-            }
-            commits = compareResult.data.commits.concat(commits)
-            compareHead = `${commits[0].sha}^`
-        }
+    core.info(
+      `Found ${commits.length} commits from the GitHub API for ${owner}/${repo}`
+    )
+    return commits.map(commit => ({
+      sha: commit.sha,
+      summary: commit.commit.message.split('\n')[0],
+      message: commit.commit.message,
+      date: moment(commit.commit.committer.date),
+      author: commit.commit.author.name,
+      prNumber: undefined
+    }))
+  }
 
-        core.info(`Found ${commits.length} commits from the GitHub API for ${owner}/${repo}`)
-        return commits.map(commit => ({
-            sha: commit.sha,
-            summary: commit.commit.message.split("\n")[0],
-            message: commit.commit.message,
-            date: moment(commit.commit.committer.date),
-            author: commit.commit.author.name,
-            prNumber: undefined
-        }))
+  private sortCommits(commits: CommitInfo[]): CommitInfo[] {
+    const commitsResult = []
+    const shas: {[key: string]: boolean} = {}
+
+    for (const commit of commits) {
+      if (shas[commit.sha]) {
+        continue
+      }
+      shas[commit.sha] = true
+      commitsResult.push(commit)
     }
 
-    private sortCommits(commits: CommitInfo[]): CommitInfo[] {
-        const commitsResult = []
-        const shas: { [key: string]: boolean } = {}
+    commitsResult.sort((a, b) => {
+      if (a.date.isBefore(b.date)) {
+        return -1
+      } else if (b.date.isBefore(a.date)) {
+        return 1
+      }
+      return 0
+    })
 
-        for (const commit of commits) {
-            if (shas[commit.sha]) {
-                continue
-            }
-            shas[commit.sha] = true
-            commitsResult.push(commit)
-        }
-
-        commitsResult.sort((a, b) => {
-            if (a.date.isBefore(b.date)) {
-                return -1
-            } else if (b.date.isBefore(a.date)) {
-                return 1
-            }
-            return 0
-        })
-
-        return commitsResult
-    }
+    return commitsResult
+  }
 }
diff --git a/src/configuration.ts b/src/configuration.ts
index fb0201d..ead0b38 100644
--- a/src/configuration.ts
+++ b/src/configuration.ts
@@ -1,27 +1,27 @@
-interface Configuration {
-    sort: string;
-    template: string;
-    pr_template: string;
-    empty_template: string;
-    categories: Array<Category>;
-    transformers: Array<Transformer>;
+export interface Configuration {
+  sort: string
+  template: string
+  pr_template: string
+  empty_template: string
+  categories: Category[]
+  transformers: Transformer[]
 }
 
-interface Category {
-    title: string;
-    labels: Array<string>;
+export interface Category {
+  title: string
+  labels: string[]
 }
 
-interface Transformer {
-    pattern: string;
-    target: string;
+export interface Transformer {
+  pattern: string
+  target: string
 }
 
-const DefaultConfiguration: Configuration = {
-    sort: "ASC",
-    template: "${{CHANGELOG}}",
-    pr_template: "- ${{TITLE}}\n   - PR: #${{NUMBER}}",
-    empty_template: "- no changes",
-    categories: [],
-    transformers: []
+export const DefaultConfiguration: Configuration = {
+  sort: 'ASC',
+  template: '${{CHANGELOG}}',
+  pr_template: '- ${{TITLE}}\n   - PR: #${{NUMBER}}',
+  empty_template: '- no changes',
+  categories: [],
+  transformers: []
 }
diff --git a/src/git-helper.ts b/src/git-helper.ts
index 5e805a9..25b5c94 100644
--- a/src/git-helper.ts
+++ b/src/git-helper.ts
@@ -1,108 +1,115 @@
-import * as core from '@actions/core'
 import * as exec from '@actions/exec'
 import * as fs from 'fs'
 import * as io from '@actions/io'
 
 export async function createCommandManager(
-    workingDirectory: string
+  workingDirectory: string
 ): Promise<GitCommandManager> {
-    return await GitCommandManager.createCommandManager(workingDirectory)
+  return await GitCommandManager.createCommandManager(workingDirectory)
 }
 
-
 function directoryExistsSync(path: string, required?: boolean): boolean {
-    if (!path) {
-        throw new Error("Arg 'path' must not be empty")
-    }
+  if (!path) {
+    throw new Error("Arg 'path' must not be empty")
+  }
 
-    let stats: fs.Stats
-    try {
-        stats = fs.statSync(path)
-    } catch (error) {
-        if (error.code === 'ENOENT') {
-            if (!required) {
-                return false
-            }
-
-            throw new Error(`Directory '${path}' does not exist`)
-        }
-
-        throw new Error(
-            `Encountered an error when checking whether path '${path}' exists: ${error.message}`
-        )
-    }
-
-    if (stats.isDirectory()) {
-        return true
-    } else if (!required) {
+  let stats: fs.Stats
+  try {
+    stats = fs.statSync(path)
+  } catch (error) {
+    if (error.code === 'ENOENT') {
+      if (!required) {
         return false
+      }
+
+      throw new Error(`Directory '${path}' does not exist`)
     }
 
-    throw new Error(`Directory '${path}' does not exist`)
+    throw new Error(
+      `Encountered an error when checking whether path '${path}' exists: ${error.message}`
+    )
+  }
+
+  if (stats.isDirectory()) {
+    return true
+  } else if (!required) {
+    return false
+  }
+
+  throw new Error(`Directory '${path}' does not exist`)
 }
 
-
 class GitCommandManager {
-    private gitPath = ''
-    private workingDirectory = ''
+  private gitPath = ''
+  private workingDirectory = ''
 
-    // Private constructor; use createCommandManager()
-    private constructor() { }
+  // Private constructor; use createCommandManager()
+  private constructor() {}
 
-    getWorkingDirectory(): string {
-        return this.workingDirectory
-    }
+  getWorkingDirectory(): string {
+    return this.workingDirectory
+  }
 
-    async latestTag(): Promise<string> {
-        const revListOutput = await this.execGit(['rev-list', '--tags', '--skip=0', '--max-count=1'])
-        const output = await this.execGit(['describe', '--abbrev=0', '--tags', revListOutput.stdout.trim()])
-        return output.stdout.trim()
-    }
+  async latestTag(): Promise<string> {
+    const revListOutput = await this.execGit([
+      'rev-list',
+      '--tags',
+      '--skip=0',
+      '--max-count=1'
+    ])
+    const output = await this.execGit([
+      'describe',
+      '--abbrev=0',
+      '--tags',
+      revListOutput.stdout.trim()
+    ])
+    return output.stdout.trim()
+  }
 
-    static async createCommandManager(
-        workingDirectory: string
-    ): Promise<GitCommandManager> {
-        const result = new GitCommandManager()
-        await result.initializeCommandManager(workingDirectory)
-        return result
-    }
+  static async createCommandManager(
+    workingDirectory: string
+  ): Promise<GitCommandManager> {
+    const result = new GitCommandManager()
+    await result.initializeCommandManager(workingDirectory)
+    return result
+  }
 
-    private async execGit(
-        args: string[],
-        allowAllExitCodes = false,
-        silent = false
-    ): Promise<GitOutput> {
-        directoryExistsSync(this.workingDirectory, true)
+  private async execGit(
+    args: string[],
+    allowAllExitCodes = false,
+    silent = false
+  ): Promise<GitOutput> {
+    directoryExistsSync(this.workingDirectory, true)
 
-        const result = new GitOutput()
+    const result = new GitOutput()
 
-        const stdout: string[] = []
+    const stdout: string[] = []
 
-        const options = {
-            cwd: this.workingDirectory,
-            silent,
-            ignoreReturnCode: allowAllExitCodes,
-            listeners: {
-                stdout: (data: Buffer) => {
-                    stdout.push(data.toString())
-                }
-            }
+    const options = {
+      cwd: this.workingDirectory,
+      silent,
+      ignoreReturnCode: allowAllExitCodes,
+      listeners: {
+        stdout: (data: Buffer) => {
+          stdout.push(data.toString())
         }
-
-        result.exitCode = await exec.exec(`"${this.gitPath}"`, args, options)
-        result.stdout = stdout.join('')
-        return result
+      }
     }
 
-    private async initializeCommandManager(
-        workingDirectory: string
-    ): Promise<void> {
-        this.workingDirectory = workingDirectory
-        this.gitPath = await io.which('git', true)
-    }
+    result.exitCode = await exec.exec(`"${this.gitPath}"`, args, options)
+    result.stdout = stdout.join('')
+    return result
+  }
+
+  private async initializeCommandManager(
+    workingDirectory: string
+  ): Promise<void> {
+    this.workingDirectory = workingDirectory
+    this.gitPath = await io.which('git', true)
+  }
 }
 
 class GitOutput {
-    stdout = ''
-    exitCode = 0
-}
\ No newline at end of file
+  stdout = ''
+  exitCode = 0
+}
diff --git a/src/main.ts b/src/main.ts
index 7b70037..3d3404c 100644
--- a/src/main.ts
+++ b/src/main.ts
@@ -1,11 +1,9 @@
 import * as core from '@actions/core'
-import { wait } from './wait'
-import { readConfiguration } from './utils';
-import { ReleaseNotes } from './releaseNotes';
-import { createCommandManager } from './git-helper';
+import {readConfiguration} from './utils'
+import {ReleaseNotes} from './releaseNotes'
+import {createCommandManager} from './git-helper'
 import * as github from '@actions/github'
-import * as path from 'path';
-
+import * as path from 'path'
 
 async function run(): Promise<void> {
   try {
@@ -17,10 +15,7 @@ async function run(): Promise<void> {
     core.debug(`GITHUB_WORKSPACE = '${githubWorkspacePath}'`)
 
     let repositoryPath = core.getInput('path') || '.'
-    repositoryPath = path.resolve(
-      githubWorkspacePath,
-      repositoryPath
-    )
+    repositoryPath = path.resolve(githubWorkspacePath, repositoryPath)
     core.debug(`repositoryPath = '${repositoryPath}'`)
 
     const configurationFile: string = core.getInput('configuration')
@@ -31,12 +26,12 @@ async function run(): Promise<void> {
     core.debug(`configurationPath = '${configurationPath}'`)
     const configuration = readConfiguration(configurationPath)
 
-    let token = core.getInput('token')
+    const token = core.getInput('token')
     let owner = core.getInput('owner')
     let repo = core.getInput('repo')
 
-    let fromTag = core.getInput("fromTag")
-    let toTag = core.getInput("toTag")
+    const fromTag = core.getInput('fromTag')
+    let toTag = core.getInput('toTag')
 
     if (!toTag) {
       // if not specified try to retrieve tag from git
@@ -48,10 +43,16 @@ async function run(): Promise<void> {
 
     if (!owner || !repo) {
       // Qualified repository
-      const qualifiedRepository = core.getInput('repository') || `${github.context.repo.owner}/${github.context.repo.repo}`
+      const qualifiedRepository =
+        core.getInput('repository') ||
+        `${github.context.repo.owner}/${github.context.repo.repo}`
       core.debug(`qualified repository = '${qualifiedRepository}'`)
       const splitRepository = qualifiedRepository.split('/')
-      if (splitRepository.length !== 2 || !splitRepository[0] || !splitRepository[1]) {
+      if (
+        splitRepository.length !== 2 ||
+        !splitRepository[0] ||
+        !splitRepository[1]
+      ) {
         throw new Error(
           `Invalid repository '${qualifiedRepository}'. Expected format {owner}/{repo}.`
         )
@@ -76,11 +77,11 @@ async function run(): Promise<void> {
     }
 
     const releaseNotes = new ReleaseNotes({
-      owner: owner,
-      repo: repo,
-      fromTag: fromTag,
-      toTag: toTag,
-      configuration: configuration
+      owner,
+      repo,
+      fromTag,
+      toTag,
+      configuration
     })
 
     core.setOutput('changelog', await releaseNotes.pull(token))
diff --git a/src/pullRequests.ts b/src/pullRequests.ts
index 606404d..4ce4a88 100755
--- a/src/pullRequests.ts
+++ b/src/pullRequests.ts
@@ -1,126 +1,143 @@
-import { Octokit, RestEndpointMethodTypes } from "@octokit/rest"
-import moment from 'moment';
+import {Octokit, RestEndpointMethodTypes} from '@octokit/rest'
+import moment from 'moment'
 
-import { CommitInfo } from "./commits"
-import * as core from '@actions/core';
+import {CommitInfo} from './commits'
+import * as core from '@actions/core'
 
 export interface PullRequestInfo {
-    number: number
-    title: string
-    htmlURL: string
-    mergedAt: moment.Moment
-    author: string
-    repoName: string
-    labels: Array<string>
-    body: string
+  number: number
+  title: string
+  htmlURL: string
+  mergedAt: moment.Moment
+  author: string
+  repoName: string
+  labels: string[]
+  body: string
 }
 
 export class PullRequests {
-    constructor(private octokit: Octokit) {}
+  constructor(private octokit: Octokit) {}
 
-    async getSingle(owner: string, repo: string, prNumber: number): Promise<PullRequestInfo | null> {
-        try {
-            const pr = await this.octokit.pulls.get({ owner, repo, pull_number: prNumber })
+  async getSingle(
+    owner: string,
+    repo: string,
+    prNumber: number
+  ): Promise<PullRequestInfo | null> {
+    try {
+      const pr = await this.octokit.pulls.get({
+        owner,
+        repo,
+        pull_number: prNumber
+      })
 
-            return {
-                number: pr.data.number,
-                title: pr.data.title,
-                htmlURL: pr.data.html_url,
-                mergedAt: moment(pr.data.merged_at),
-                author: pr.data.user.login,
-                repoName: pr.data.base.repo.full_name,
-                labels: pr.data.labels.map(function (label) { return label.name }),
-                body: pr.data.body
-            }
-        } catch (e) {
-            core.warning(`Cannot find PR ${owner}/${repo}#${prNumber} - ${e.message}`)
-            return null
-        }
+      return {
+        number: pr.data.number,
+        title: pr.data.title,
+        htmlURL: pr.data.html_url,
+        mergedAt: moment(pr.data.merged_at),
+        author: pr.data.user.login,
+        repoName: pr.data.base.repo.full_name,
+        labels: pr.data.labels.map(function (label) {
+          return label.name
+        }),
+        body: pr.data.body
+      }
+    } catch (e) {
+      core.warning(`Cannot find PR ${owner}/${repo}#${prNumber} - ${e.message}`)
+      return null
     }
+  }
 
-    async getBetweenDates(
-        owner: string,
-        repo: string,
-        fromDate: moment.Moment,
-        toDate: moment.Moment
-    ): Promise<PullRequestInfo[]> {
-        const mergedPRs: PullRequestInfo[] = []
-        const options = this.octokit.pulls.list.endpoint.merge({
-            owner,
-            repo,
-            state: "closed",
-            sort: "updated",
-            direction: "desc"
-        })
+  async getBetweenDates(
+    owner: string,
+    repo: string,
+    fromDate: moment.Moment,
+    toDate: moment.Moment
+  ): Promise<PullRequestInfo[]> {
+    const mergedPRs: PullRequestInfo[] = []
+    const options = this.octokit.pulls.list.endpoint.merge({
+      owner,
+      repo,
+      state: 'closed',
+      sort: 'updated',
+      direction: 'desc'
+    })
 
-        for await (const response of this.octokit.paginate.iterator(options)) {
-            type PullsListData = RestEndpointMethodTypes["pulls"]["list"]["response"]["data"]
-            const prs: PullsListData = response.data as PullsListData
-
-            const firstPR = prs[0]
-            if(firstPR.merged_at && fromDate.isAfter(moment(firstPR.merged_at))) {
-                // bail out early to not keep iterating on PRs super old
-                return sortPullRequests(mergedPRs, true)
-            }
-
-            prs.filter(
-                pr =>
-                    !!pr.merged_at &&
-                    fromDate.isBefore(moment(pr.merged_at)) &&
-                    toDate.isSameOrAfter(moment(pr.merged_at))
-            ).forEach(pr => {
-                mergedPRs.push({
-                    number: pr.number,
-                    title: pr.title,
-                    htmlURL: pr.html_url,
-                    mergedAt: moment(pr.merged_at),
-                    author: pr.user.login,
-                    repoName: pr.base.repo.full_name,
-                    labels: pr.labels.map(function (label) { return label.name }),
-                    body: pr.body
-                })
-            })
-        }
+    for await (const response of this.octokit.paginate.iterator(options)) {
+      type PullsListData = RestEndpointMethodTypes['pulls']['list']['response']['data']
+      const prs: PullsListData = response.data as PullsListData
 
+      const firstPR = prs[0]
+      if (firstPR.merged_at && fromDate.isAfter(moment(firstPR.merged_at))) {
+        // bail out early to not keep iterating on PRs super old
         return sortPullRequests(mergedPRs, true)
+      }
+
+      prs
+        .filter(
+          pr =>
+            !!pr.merged_at &&
+            fromDate.isBefore(moment(pr.merged_at)) &&
+            toDate.isSameOrAfter(moment(pr.merged_at))
+        )
+        .forEach(pr => {
+          mergedPRs.push({
+            number: pr.number,
+            title: pr.title,
+            htmlURL: pr.html_url,
+            mergedAt: moment(pr.merged_at),
+            author: pr.user.login,
+            repoName: pr.base.repo.full_name,
+            labels: pr.labels.map(function (label) {
+              return label.name
+            }),
+            body: pr.body
+          })
+        })
     }
 
-    filterCommits(commits: CommitInfo[]): CommitInfo[] {
-        const prRegex = /Merge pull request #(\d+)/
-        const filteredCommits = []
+    return sortPullRequests(mergedPRs, true)
+  }
 
-        for (const commit of commits) {
-            const match = commit.summary.match(prRegex)
-            if (!match) {
-                continue
-            }
-            commit.prNumber = Number.parseInt(match[1], 10)
-            filteredCommits.push(commit)
-        }
+  filterCommits(commits: CommitInfo[]): CommitInfo[] {
+    const prRegex = /Merge pull request #(\d+)/
+    const filteredCommits = []
 
-        return filteredCommits
+    for (const commit of commits) {
+      const match = commit.summary.match(prRegex)
+      if (!match) {
+        continue
+      }
+      commit.prNumber = Number.parseInt(match[1], 10)
+      filteredCommits.push(commit)
     }
+
+    return filteredCommits
+  }
 }
 
-export function sortPullRequests(pullRequests: PullRequestInfo[], ascending: Boolean): PullRequestInfo[] {
-    if(ascending) {
-        pullRequests.sort((a, b) => {
-            if (a.mergedAt.isBefore(b.mergedAt)) {
-                return -1
-            } else if (b.mergedAt.isBefore(a.mergedAt)) {
-                return 1
-            }
-            return 0
-        })
-    } else {
-        pullRequests.sort((b, a) => {
-            if (a.mergedAt.isBefore(b.mergedAt)) {
-                return -1
-            } else if (b.mergedAt.isBefore(a.mergedAt)) {
-                return 1
-            }
-            return 0
-        })
-    }
-    return pullRequests
-}
\ No newline at end of file
+export function sortPullRequests(
+  pullRequests: PullRequestInfo[],
+  ascending: Boolean
+): PullRequestInfo[] {
+  if (ascending) {
+    pullRequests.sort((a, b) => {
+      if (a.mergedAt.isBefore(b.mergedAt)) {
+        return -1
+      } else if (b.mergedAt.isBefore(a.mergedAt)) {
+        return 1
+      }
+      return 0
+    })
+  } else {
+    pullRequests.sort((b, a) => {
+      if (a.mergedAt.isBefore(b.mergedAt)) {
+        return -1
+      } else if (b.mergedAt.isBefore(a.mergedAt)) {
+        return 1
+      }
+      return 0
+    })
+  }
+  return pullRequests
+}
diff --git a/src/releaseNotes.ts b/src/releaseNotes.ts
index ba248ea..8de1267 100755
--- a/src/releaseNotes.ts
+++ b/src/releaseNotes.ts
@@ -1,107 +1,124 @@
-import { Octokit } from "@octokit/rest"
-
-import { Commits } from "./commits"
-import { PullRequestInfo, PullRequests } from "./pullRequests"
-import { buildChangelog } from './transform';
-import * as core from '@actions/core';
-import { Tags } from './tags';
+import {Octokit} from '@octokit/rest'
+import {Commits} from './commits'
+import {PullRequestInfo, PullRequests} from './pullRequests'
+import {buildChangelog} from './transform'
+import * as core from '@actions/core'
+import {Tags} from './tags'
+import {Configuration, DefaultConfiguration} from './configuration'
 
 export interface ReleaseNotesOptions {
-    owner: string
-    repo: string
-    fromTag: string | null
-    toTag: string
-    configuration: Configuration
+  owner: string
+  repo: string
+  fromTag: string | null
+  toTag: string
+  configuration: Configuration
 }
 
 export class ReleaseNotes {
-    constructor(private options: ReleaseNotesOptions) {
+  constructor(private options: ReleaseNotesOptions) {}
 
+  async pull(token?: string): Promise<string> {
+    const octokit = new Octokit({
+      auth: `token ${token || process.env.GITHUB_TOKEN}`
+    })
+
+    const {owner, repo, fromTag, toTag, configuration} = this.options
+
+    if (!fromTag) {
+      const tagsApi = new Tags(octokit)
+
+      const previousTag = await tagsApi.findPredecessorTag(owner, repo, toTag)
+      if (previousTag == null) {
+        core.error(`Unable to retrieve previous tag given ${toTag}`)
+        return configuration.empty_template
+          ? configuration.empty_template
+          : DefaultConfiguration.empty_template
+      }
+
+      this.options.fromTag = previousTag.name
     }
 
-    async pull(token?: string): Promise<string> {
-        const octokit = new Octokit({
-            auth: `token ${token || process.env.GITHUB_TOKEN}`
-        })
+    const mergedPullRequests = await this.getMergedPullRequests(octokit)
 
-        const { owner, repo, fromTag, toTag, configuration } = this.options
-
-        if(fromTag == null) {
-            const tagsApi = new Tags(octokit)
-
-            const previousTag = await tagsApi.findPredecessorTag(owner, repo, toTag)
-            if(previousTag == null) {
-                core.error(`Unable to retrieve previous tag given ${toTag}`)
-                return configuration.empty_template ? configuration.empty_template : DefaultConfiguration.empty_template
-            }
-
-            this.options.fromTag = previousTag.name
-        }
-
-        const mergedPullRequests = await this.getMergedPullRequests(octokit)
-
-        if (mergedPullRequests.length == 0) {
-            core.warning(`No pull requests found for between ${fromTag}...${toTag}`)
-            return configuration.empty_template ? configuration.empty_template : DefaultConfiguration.empty_template
-        }
-
-        return buildChangelog(mergedPullRequests, configuration)
+    if (mergedPullRequests.length === 0) {
+      core.warning(`No pull requests found for between ${fromTag}...${toTag}`)
+      return configuration.empty_template
+        ? configuration.empty_template
+        : DefaultConfiguration.empty_template
     }
 
-    private async getMergedPullRequests(octokit: Octokit): Promise<PullRequestInfo[]> {
-        const { owner, repo, fromTag, toTag } = this.options
-        core.info(`Comparing ${owner}/${repo} ${fromTag}...${toTag}`)
+    return buildChangelog(mergedPullRequests, configuration)
+  }
 
-        const commitsApi = new Commits(octokit)
-        const commits = await commitsApi.getDiff(owner, repo, fromTag!!, toTag)
+  private async getMergedPullRequests(
+    octokit: Octokit
+  ): Promise<PullRequestInfo[]> {
+    const {owner, repo, fromTag, toTag} = this.options
+    core.info(`Comparing ${owner}/${repo} ${fromTag}...${toTag}`)
 
-        if (commits.length === 0) {
-            return []
-        }
+    const commitsApi = new Commits(octokit)
+    const commits = await commitsApi.getDiff(owner, repo, fromTag!!, toTag)
 
-        const firstCommit = commits[0]
-        const lastCommit = commits[commits.length - 1]
-        const fromDate = firstCommit.date
-        const toDate = lastCommit.date
-
-        core.info(`Fetching PRs between dates ${fromDate.toISOString()} ${toDate.toISOString()} for ${owner}/${repo}`)
-
-        const pullRequestsApi = new PullRequests(octokit)
-        const pullRequests = await pullRequestsApi.getBetweenDates(owner, repo, fromDate, toDate)
-
-        core.info(`Found ${pullRequests.length} merged PRs for ${owner}/${repo}`)
-
-        const prCommits = pullRequestsApi.filterCommits(commits)
-        const filteredPullRequests = []
-        const pullRequestsByNumber: { [key: number]: PullRequestInfo } = {}
-
-        for (const pr of pullRequests) {
-            pullRequestsByNumber[pr.number] = pr
-        }
-
-        for (const commit of prCommits) {
-            if (!commit.prNumber) {
-                continue
-            }
-
-            const prRef = `${owner}/${repo}#${commit.prNumber}`
-
-            if (pullRequestsByNumber[commit.prNumber]) {
-                filteredPullRequests.push(pullRequestsByNumber[commit.prNumber])
-            } else if (fromDate.toISOString() === toDate.toISOString()) {
-                core.info(`${prRef} not in date range, fetching explicitly`)
-                const pullRequest = await pullRequestsApi.getSingle(owner, repo, commit.prNumber)
-
-                if (pullRequest) {
-                    filteredPullRequests.push(pullRequest)
-                } else {
-                    core.warning(`${prRef} not found! Commit text: ${commit.summary}`)
-                }
-            } else {
-                core.info(`${prRef} not in date range, likely a merge commit from a fork-to-fork PR`)
-            }
-        }
-
-        return filteredPullRequests
+    if (commits.length === 0) {
+      return []
     }
+
+    const firstCommit = commits[0]
+    const lastCommit = commits[commits.length - 1]
+    const fromDate = firstCommit.date
+    const toDate = lastCommit.date
+
+    core.info(
+      `Fetching PRs between dates ${fromDate.toISOString()} ${toDate.toISOString()} for ${owner}/${repo}`
+    )
+
+    const pullRequestsApi = new PullRequests(octokit)
+    const pullRequests = await pullRequestsApi.getBetweenDates(
+      owner,
+      repo,
+      fromDate,
+      toDate
+    )
+
+    core.info(`Found ${pullRequests.length} merged PRs for ${owner}/${repo}`)
+
+    const prCommits = pullRequestsApi.filterCommits(commits)
+    const filteredPullRequests = []
+    const pullRequestsByNumber: {[key: number]: PullRequestInfo} = {}
+
+    for (const pr of pullRequests) {
+      pullRequestsByNumber[pr.number] = pr
+    }
+
+    for (const commit of prCommits) {
+      if (!commit.prNumber) {
+        continue
+      }
+
+      const prRef = `${owner}/${repo}#${commit.prNumber}`
+
+      if (pullRequestsByNumber[commit.prNumber]) {
+        filteredPullRequests.push(pullRequestsByNumber[commit.prNumber])
+      } else if (fromDate.toISOString() === toDate.toISOString()) {
+        core.info(`${prRef} not in date range, fetching explicitly`)
+        const pullRequest = await pullRequestsApi.getSingle(
+          owner,
+          repo,
+          commit.prNumber
+        )
+
+        if (pullRequest) {
+          filteredPullRequests.push(pullRequest)
+        } else {
+          core.warning(`${prRef} not found! Commit text: ${commit.summary}`)
+        }
+      } else {
+        core.info(
+          `${prRef} not in date range, likely a merge commit from a fork-to-fork PR`
+        )
+      }
+    }
+
+    return filteredPullRequests
+  }
 }
diff --git a/src/tags.ts b/src/tags.ts
index 289311b..a47162a 100755
--- a/src/tags.ts
+++ b/src/tags.ts
@@ -1,83 +1,86 @@
-import { Octokit, RestEndpointMethodTypes } from '@octokit/rest';
-import * as core from '@actions/core';
-import { PullRequestInfo } from './pullRequests';
+import {Octokit, RestEndpointMethodTypes} from '@octokit/rest'
+import * as core from '@actions/core'
 
 export interface TagInfo {
-    name: string,
-    commit: string
+  name: string
+  commit: string
 }
 
 export class Tags {
-    constructor(private octokit: Octokit) { }
+  constructor(private octokit: Octokit) {}
 
-    async getTags(owner: string, repo: string): Promise<TagInfo[]> {
-        const tagsInfo: TagInfo[] = []
-        const options = this.octokit.repos.listTags.endpoint.merge({
-            owner,
-            repo,
-            direction: "desc",
-            per_page: 100
+  async getTags(owner: string, repo: string): Promise<TagInfo[]> {
+    const tagsInfo: TagInfo[] = []
+    const options = this.octokit.repos.listTags.endpoint.merge({
+      owner,
+      repo,
+      direction: 'desc',
+      per_page: 100
+    })
+
+    const max = 200
+    for await (const response of this.octokit.paginate.iterator(options)) {
+      type TagsListData = RestEndpointMethodTypes['repos']['listTags']['response']['data']
+      const tags: TagsListData = response.data as TagsListData
+
+      tags.forEach(tag => {
+        tagsInfo.push({
+          name: tag.name,
+          commit: tag.commit.sha
         })
+      })
 
-        const max: number = 200
-        for await (const response of this.octokit.paginate.iterator(options)) {
-            type TagsListData = RestEndpointMethodTypes["repos"]["listTags"]["response"]["data"]
-            const tags: TagsListData = response.data as TagsListData
+      // for performance only fetch newest 200 tags!!
+      if (tagsInfo.length >= max) {
+        break
+      }
+    }
 
-            tags.forEach(tag => {
-                tagsInfo.push({
-                    name: tag.name,
-                    commit: tag.commit.sha
-                })
-            })
+    core.info(
+      `Found ${tagsInfo.length} (fetching max: ${max}) tags from the GitHub API for ${owner}/${repo}`
+    )
+    return tagsInfo
+  }
 
-            // for performance only fetch newest 200 tags!!
-            if (tagsInfo.length >= max) {
-                break
-            }
+  async findPredecessorTag(
+    owner: string,
+    repo: string,
+    tag: string
+  ): Promise<TagInfo | null> {
+    const tags = this.sortTags(await this.getTags(owner, repo))
+
+    const length = tags.length
+    for (let i = 0; i < length; i++) {
+      if (tags[i].name.toLowerCase() === tag.toLowerCase()) {
+        return tags[i + 1]
+      }
+    }
+
+    // not found, throw exception?
+    return tags[0]
+  }
+
+  private sortTags(commits: TagInfo[]): TagInfo[] {
+    commits.sort((b, a) => {
+      const partsA = a.name.replace(/^v/, '').split('-')
+      const partsB = b.name.replace(/^v/, '').split('-')
+      const versionCompare = partsA[0].localeCompare(partsB[0])
+      if (versionCompare !== 0) {
+        return versionCompare
+      } else {
+        if (partsA.length === 1) {
+          return 0
+        } else if (partsB.length === 1) {
+          return 1
+        } else {
+          return partsA[1].localeCompare(partsB[1])
         }
-
-        core.info(`Found ${tagsInfo.length} (fetching max: ${max}) tags from the GitHub API for ${owner}/${repo}`)
-        return tagsInfo
-    }
-
-
-    async findPredecessorTag(owner: string, repo: string, tag: string): Promise<TagInfo | null> {
-        const tags = this.sortTags(await this.getTags(owner, repo))
-
-        var length = tags.length;
-        for (var i = 0; i < length; i++) {
-            if (tags[i].name.toLowerCase() === tag.toLowerCase()) {
-                return tags[i + 1]
-            }
-        }
-
-        // not found, throw exception?
-        return tags[0]
-    }
-
-    private sortTags(commits: TagInfo[]): TagInfo[] {
-        commits.sort((b, a) => {
-            const partsA = a.name.replace(/^v/, '').split('-')
-            const partsB = b.name.replace(/^v/, '').split('-')
-            const versionCompare = partsA[0].localeCompare(partsB[0])
-            if(versionCompare != 0) {
-                return versionCompare
-            } else {
-                if(partsA.length == 1) {
-                    return 0
-                } else if(partsB.length == 1) {
-                    return 1
-                } else {
-                    return partsA[1].localeCompare(partsB[1])
-                }
-            }
-        })
-        return commits
-    }
+      }
+    })
+    return commits
+  }
 }
 
-
 /*
 
 2020.3.2 ( should resolve 2020.3.1 )
@@ -93,4 +96,4 @@ export class Tags {
 2020.3.1-a01
 
 2020.3.0
-*/
\ No newline at end of file
+*/
diff --git a/src/transform.ts b/src/transform.ts
index c3bc2e8..db029b9 100644
--- a/src/transform.ts
+++ b/src/transform.ts
@@ -1,114 +1,126 @@
-import { PullRequestInfo, sortPullRequests } from './pullRequests';
-import * as core from '@actions/core';
+import {PullRequestInfo, sortPullRequests} from './pullRequests'
+import * as core from '@actions/core'
+import {Category, Configuration, Transformer} from './configuration'
 
-export function buildChangelog(prs: PullRequestInfo[], config: Configuration): string {
-    // sort to target order
-    prs = sortPullRequests(prs, config.sort.toUpperCase() === "ASC")
+export function buildChangelog(
+  prs: PullRequestInfo[],
+  config: Configuration
+): string {
+  // sort to target order
+  prs = sortPullRequests(prs, config.sort.toUpperCase() === 'ASC')
 
-    const validatedTransformers = validateTransfomers(config.transformers)
-    let transformedMap = new Map<PullRequestInfo, string>();
-    // convert PRs to their text representation
-    prs.forEach(pr => {
-        transformedMap.set(pr, transform(fillTemplate(pr, config.pr_template), validatedTransformers))
+  const validatedTransformers = validateTransfomers(config.transformers)
+  const transformedMap = new Map<PullRequestInfo, string>()
+  // convert PRs to their text representation
+  prs.forEach(pr => {
+    transformedMap.set(
+      pr,
+      transform(fillTemplate(pr, config.pr_template), validatedTransformers)
+    )
+  })
+
+  // bring PRs into the order of categories
+  const categorized = new Map<Category, string[]>()
+  config.categories.forEach(category => {
+    categorized.set(category, [])
+  })
+  const uncategorized: string[] = []
+
+  // bring elements in order
+  transformedMap.forEach((body, pr) => {
+    let matched = false
+
+    categorized.forEach((pullRequests, category) => {
+      if (haveCommonElements(category.labels, pr.labels)) {
+        pullRequests.push(body)
+        matched = true
+      }
     })
 
-    // bring PRs into the order of categories
-    let categorized = new Map<Category, string[]>();
-    config.categories.forEach(category => {
-        categorized.set(category, [])
-    })
-    let uncategorized: Array<string> = [];
+    if (!matched) {
+      uncategorized.push(body)
+    }
+  })
 
-    // bring elements in order
-    transformedMap.forEach((body, pr) => {
-        let matched = false
+  // construct final changelog
+  let changelog = ''
+  categorized.forEach((pullRequests, category) => {
+    if (pullRequests.length > 0) {
+      changelog = `${changelog + category.title}\n\n`
 
-        categorized.forEach((prs, category) => {
-            if (findCommonElements3(category.labels, pr.labels)) {
-                prs.push(body)
-                matched = true
-            }
-        })
+      pullRequests.forEach(pr => {
+        changelog = `${changelog + pr}\n`
+      })
 
-        if (!matched) {
-            uncategorized.push(body)
-        }
-    })
+      // add space between
+      changelog = `${changelog}\n`
+    }
+  })
 
-    // construct final changelog
-    let changelog = ""
-    categorized.forEach((prs, category) => {
-        if (prs.length > 0) {
-            changelog = changelog + category.title + "\n\n"
+  let changelogUncategorized = ''
+  uncategorized.forEach(pr => {
+    changelogUncategorized = `${changelogUncategorized + pr}\n`
+  })
 
-            prs.forEach(pr => {
-                changelog = changelog + pr + "\n"
-            })
-
-            // add space between
-            changelog = changelog + "\n"
-        }
-    })
-
-    let changelogUncategorized = ""
-    uncategorized.forEach(pr => {
-        changelogUncategorized = changelogUncategorized + pr + "\n"
-    })
-
-    // fill template
-    let transformedChangelog = config.template
-    transformedChangelog = transformedChangelog.replace("${{CHANGELOG}}", changelog)
-    transformedChangelog = transformedChangelog.replace("${{UNCATEGORIZED}}", changelogUncategorized)
-    return transformedChangelog;
+  // fill template
+  let transformedChangelog = config.template
+  transformedChangelog = transformedChangelog.replace(
+    '${{CHANGELOG}}',
+    changelog
+  )
+  transformedChangelog = transformedChangelog.replace(
+    '${{UNCATEGORIZED}}',
+    changelogUncategorized
+  )
+  return transformedChangelog
 }
 
-function findCommonElements3(arr1: string[], arr2: string[]) {
-    return arr1.some(item => arr2.includes(item))
+function haveCommonElements(arr1: string[], arr2: string[]): Boolean {
+  return arr1.some(item => arr2.includes(item))
 }
 
 function fillTemplate(pr: PullRequestInfo, template: string): string {
-    let transformed = template
-    transformed = transformed.replace("${{NUMBER}}", pr.number.toString())
-    transformed = transformed.replace("${{TITLE}}", pr.title)
-    transformed = transformed.replace("${{URL}}", pr.htmlURL)
-    transformed = transformed.replace("${{MERGED_AT}}", pr.mergedAt.toString)
-    transformed = transformed.replace("${{AUTHOR}}", pr.author)
-    transformed = transformed.replace("${{BODY}}", pr.body)
-    return transformed
+  let transformed = template
+  transformed = transformed.replace('${{NUMBER}}', pr.number.toString())
+  transformed = transformed.replace('${{TITLE}}', pr.title)
+  transformed = transformed.replace('${{URL}}', pr.htmlURL)
+  transformed = transformed.replace('${{MERGED_AT}}', pr.mergedAt.toString())
+  transformed = transformed.replace('${{AUTHOR}}', pr.author)
+  transformed = transformed.replace('${{BODY}}', pr.body)
+  return transformed
 }
 
 function transform(filled: string, transformers: RegexTransformer[]): string {
-    if (transformers.length == 0) {
-        return filled
-    }
-    let transformed = filled
-    transformers.forEach(({ pattern, target }) => {
-        transformed = transformed.replace(pattern!!, target)
-    })
-    return transformed
+  if (transformers.length === 0) {
+    return filled
+  }
+  let transformed = filled
+  transformers.forEach(({pattern, target}) => {
+    transformed = transformed.replace(pattern!!, target)
+  })
+  return transformed
 }
 
 function validateTransfomers(transformers: Transformer[]): RegexTransformer[] {
-    return transformers
-        .map((transformer) => {
-            try {
-                return {
-                    pattern: new RegExp(transformer.pattern.replace("\\\\", '\\'), "g"),
-                    target: transformer.target
-                }
-            } catch (e) {
-                core.warning(`Bad replacer regex: ${transformer.pattern}`)
-                return {
-                    pattern: null,
-                    target: ""
-                }
-            }
-        })
-        .filter(transformer => transformer.pattern != null)
+  return transformers
+    .map(transformer => {
+      try {
+        return {
+          pattern: new RegExp(transformer.pattern.replace('\\\\', '\\'), 'g'),
+          target: transformer.target
+        }
+      } catch (e) {
+        core.warning(`Bad replacer regex: ${transformer.pattern}`)
+        return {
+          pattern: null,
+          target: ''
+        }
+      }
+    })
+    .filter(transformer => transformer.pattern != null)
 }
 
-
 interface RegexTransformer {
-    pattern: RegExp | null;
-    target: string;
-}
\ No newline at end of file
+  pattern: RegExp | null
+  target: string
+}
diff --git a/src/utils.ts b/src/utils.ts
index 71c9c67..d461d05 100644
--- a/src/utils.ts
+++ b/src/utils.ts
@@ -1,7 +1,8 @@
-const fs = require("fs");
+import * as fs from 'fs'
+import {Configuration} from './configuration'
 
-export function readConfiguration(filename: string) {
-    const rawdata = fs.readFileSync(filename);
-    const configurationJSON: Configuration = JSON.parse(rawdata);
-    return configurationJSON;
-}
\ No newline at end of file
+export function readConfiguration(filename: string): Configuration {
+  const rawdata = fs.readFileSync(filename, 'utf8')
+  const configurationJSON: Configuration = JSON.parse(rawdata)
+  return configurationJSON
+}