Make it TS

package.json

@@ -89,6 +89,8 @@
 		"@babel/plugin-syntax-jsx": "7.12.13",
 		"@babel/runtime-corejs3": "7.13.10",
 		"@babel/traverse": "7.13.0",
+		"@jest/reporters": "^26.6.2",
+		"@jest/test-result": "^26.6.2",
 		"@octokit/rest": "16.26.0",
 		"@octokit/webhooks": "7.1.0",
 		"@storybook/addon-a11y": "6.2.5",

test/tsconfig.json

@@ -0,0 +1,20 @@
+{
+	"extends": "../tsconfig.base.json",
+	"compilerOptions": {
+		"module": "commonjs",
+		"esModuleInterop": true,
+		"target": "ES6",
+		"lib": [ "ES6", "ES2020.string" ],
+		"rootDir": ".",
+
+		// These scripts aren't published and packages don't depend on them.
+		// Don't generate types, this is strictly for validation.
+		"incremental": true,
+		"declaration": true,
+		"declarationMap": true,
+		"outDir": ".cache"
+	},
+	"files": [
+		"./unit/GithubActionsReporter.ts"
+	]
+}

test/unit/GithubActionsReporter.js → test/unit/GithubActionsReporter.ts

@@ -5,27 +5,30 @@
  * LICENSE file in the root directory of this source tree.
  */
 
-// import type {AggregatedResult, TestResult} from '@jest/test-result';
-// import type { Reporter, Context } from '@jest/reporters';
-// import type {Context} from './types';
-
-// const { flatMap } = require( 'lodash' );
+/**
+ * External dependencies
+ */
+import type { AggregatedResult, TestResult } from '@jest/test-result';
+import { BaseReporter, Context } from '@jest/reporters';
 
 const newLine = /\n/g;
 const encodedNewLine = '%0A';
 const lineAndColumnInStackTrace = /^.*:([0-9]+):([0-9]+).*$/;
 
-class GithubActionReporter {
-	async onRunComplete( _contexts, _aggregatedResults ) {
-		const messages = getMessages( _aggregatedResults?.testResults );
+export default class GithubActionReporter extends BaseReporter {
+	onRunComplete(
+		_contexts?: Set< Context >,
+		aggregatedResults?: AggregatedResult
+	): void {
+		const messages = getMessages( aggregatedResults?.testResults );
 
 		for ( const message of messages ) {
-			process.stderr.write( message + '\n' );
+			this.log( message );
 		}
 	}
 }
 
-function getMessages( results ) {
+function getMessages( results: Array< TestResult > | undefined ) {
 	if ( ! results ) return [];
 
 	return results.reduce(
@@ -38,7 +41,7 @@ function getMessages( results ) {
 				)
 				.map( ( m ) => m.replace( newLine, encodedNewLine ) )
 				.map( ( m ) => lineAndColumnInStackTrace.exec( m ) )
-				//.filter((m): m is RegExpExecArray => m !== null)
+				.filter( ( m ): m is RegExpExecArray => m !== null )
 				.map(
 					( [ message, line, col ] ) =>
 						`::error file=${ testFilePath },line=${ line },col=${ col }::${ message }`
@@ -48,12 +51,6 @@ function getMessages( results ) {
 	);
 }
 
-function flatMap( fn ) {
-	return ( out, entry ) => out.concat( ...fn( entry ) );
+function flatMap< In, Out >( map: ( x: In ) => Array< Out > ) {
+	return ( out: Array< Out >, entry: In ) => out.concat( ...map( entry ) );
 }
-
-// function flatMap< In, Out >( map: ( x: In ) => Array< Out > ) {
-// 	return ( out: Array< Out >, entry: In ) => out.concat( ...map( entry ) );
-// }
-
-module.exports = GithubActionReporter;

tsconfig.json

@@ -30,7 +30,8 @@
 		{ "path": "packages/token-list" },
 		{ "path": "packages/url" },
 		{ "path": "packages/warning" },
-		{ "path": "packages/wordcount" }
+		{ "path": "packages/wordcount" },
+		{ "path": "test" },
 	],
 	"files": []
 }