Add compile option

Support compilation using `tsc` before AVA runs tests.

This is a breaking change. To retain the old behavior you must configure `compile: false`.

Co-authored-by: Mark Wubben <mark@novemberborn.net>

.editorconfig

@@ -10,3 +10,6 @@ insert_final_newline = true
 [*.yml]
 indent_style = space
 indent_size = 2
+
+[package.json]
+indent_style = space

.gitignore

@@ -1,2 +1,4 @@
 /coverage
 /node_modules
+/test/fixtures/typescript/compiled
+/test/broken-fixtures/typescript/compiled

README.md

@@ -1,10 +1,10 @@
 # @ava/typescript
 
-Adds rudimentary [TypeScript](https://www.typescriptlang.org/) support to [AVA](https://avajs.dev).
+Adds [TypeScript](https://www.typescriptlang.org/) support to [AVA](https://avajs.dev).
 
-This is designed to work for projects that precompile their TypeScript code, including tests. It allows AVA to load the resulting JavaScript, while configuring AVA to use the TypeScript paths.
+This is designed to work for projects that precompile TypeScript. It allows AVA to load the compiled JavaScript, while configuring AVA to treat the TypeScript files as test files.
 
-In other words, say you have a test file at `src/test.ts`. You've configured TypeScript to output to `build/`. Using `@ava/typescript` you can run the `build/test.js` file using `npx ava src/test.ts`. AVA won't pick up any of the JavaScript files present in the `build/` directory, unless they have a TypeScript counterpart in `src/`.
+In other words, say you have a test file at `src/test.ts`. You've configured TypeScript to output to `build/`. Using `@ava/typescript` you can run the test using `npx ava src/test.ts`.
 
 ## Enabling TypeScript support
 
@@ -24,14 +24,17 @@ Then, enable TypeScript support either in `package.json` or `ava.config.*`:
 		"typescript": {
 			"rewritePaths": {
 				"src/": "build/"
-			}
+			},
+			"compile": false
 		}
 	}
 }
 ```
 
 Both keys and values of the `rewritePaths` object must end with a `/`. Paths are relative to your project directory.
 
+You can enable compilation via the `compile` property. If `false`, AVA will assume you have already compiled your project. If set to `'tsc'`, AVA will run the TypeScript compiler before running your tests. This can be inefficient when using AVA in watch mode.
+
 Output files are expected to have the `.js` extension.
 
 AVA searches your entire project for `*.js`, `*.cjs`, `*.mjs` and `*.ts` files (or other extensions you've configured). It will ignore such files found in the `rewritePaths` targets (e.g. `build/`). If you use more specific paths, for instance `build/main/`, you may need to change AVA's `files` configuration to ignore other directories.

index.js

@@ -1,31 +1,74 @@
 'use strict';
 const path = require('path');
-
 const escapeStringRegexp = require('escape-string-regexp');
-
+const execa = require('execa');
 const pkg = require('./package.json');
 
+const help = `See https://github.com/avajs/typescript/blob/v${pkg.version}/README.md`;
+
 function isPlainObject(x) {
 	return x !== null && typeof x === 'object' && Reflect.getPrototypeOf(x) === Object.prototype;
 }
 
-function isValidExtensions(extensions) {
-	return Array.isArray(extensions) &&
-		extensions.length > 0 &&
-		extensions.every(ext => typeof ext === 'string' && ext !== '') &&
-		new Set(extensions).size === extensions.length;
-}
+function validate(target, properties) {
+	for (const key of Object.keys(properties)) {
+		const {required, isValid} = properties[key];
+		const missing = !Reflect.has(target, key);
 
-function isValidRewritePaths(rewritePaths) {
-	if (!isPlainObject(rewritePaths)) {
-		return false;
+		if (missing) {
+			if (required) {
+				throw new Error(`Missing '${key}' property in TypeScript configuration for AVA. ${help}`);
+			}
+
+			continue;
+		}
+
+		if (!isValid(target[key])) {
+			throw new Error(`Invalid '${key}' property in TypeScript configuration for AVA. ${help}`);
+		}
+	}
+
+	for (const key of Object.keys(target)) {
+		if (!Reflect.has(properties, key)) {
+			throw new Error(`Unexpected '${key}' property in TypeScript configuration for AVA. ${help}`);
+		}
 	}
+}
 
-	return Object.entries(rewritePaths).every(([from, to]) => {
-		return from.endsWith('/') && typeof to === 'string' && to.endsWith('/');
-	});
+async function compileTypeScript(projectDir) {
+	return execa('tsc', ['--incremental'], {preferLocal: true, cwd: projectDir});
 }
 
+const configProperties = {
+	compile: {
+		required: true,
+		isValid(compile) {
+			return compile === false || compile === 'tsc';
+		}
+	},
+	rewritePaths: {
+		required: true,
+		isValid(rewritePaths) {
+			if (!isPlainObject(rewritePaths)) {
+				return false;
+			}
+
+			return Object.entries(rewritePaths).every(([from, to]) => {
+				return from.endsWith('/') && typeof to === 'string' && to.endsWith('/');
+			});
+		}
+	},
+	extensions: {
+		required: false,
+		isValid(extensions) {
+			return Array.isArray(extensions) &&
+				extensions.length > 0 &&
+				extensions.every(ext => typeof ext === 'string' && ext !== '') &&
+				new Set(extensions).size === extensions.length;
+		}
+	}
+};
+
 module.exports = ({negotiateProtocol}) => {
 	const protocol = negotiateProtocol(['ava-3.2'], {version: pkg.version});
 	if (protocol === null) {
@@ -34,23 +77,16 @@ module.exports = ({negotiateProtocol}) => {
 
 	return {
 		main({config}) {
-			let valid = false;
-			if (isPlainObject(config)) {
-				const keys = Object.keys(config);
-				if (keys.every(key => key === 'extensions' || key === 'rewritePaths')) {
-					valid =
-						(config.extensions === undefined || isValidExtensions(config.extensions)) &&
-						isValidRewritePaths(config.rewritePaths);
-				}
+			if (!isPlainObject(config)) {
+				throw new Error(`Unexpected Typescript configuration for AVA. ${help}`);
 			}
 
-			if (!valid) {
-				throw new Error(`Unexpected Typescript configuration for AVA. See https://github.com/avajs/typescript/blob/v${pkg.version}/README.md for allowed values.`);
-			}
+			validate(config, configProperties);
 
 			const {
 				extensions = ['ts'],
-				rewritePaths: relativeRewritePaths
+				rewritePaths: relativeRewritePaths,
+				compile
 			} = config;
 
 			const rewritePaths = Object.entries(relativeRewritePaths).map(([from, to]) => [
@@ -61,6 +97,10 @@ module.exports = ({negotiateProtocol}) => {
 
 			return {
 				async compile() {
+					if (compile === 'tsc') {
+						await compileTypeScript(protocol.projectDir);
+					}
+
 					return {
 						extensions: extensions.slice(),
 						rewritePaths: rewritePaths.slice()

package.json

@@ -19,12 +19,14 @@
     "test": "xo && c8 ava"
   },
   "dependencies": {
-    "escape-string-regexp": "^4.0.0"
+    "escape-string-regexp": "^4.0.0",
+    "execa": "^5.0.0"
   },
   "devDependencies": {
     "ava": "^3.15.0",
     "c8": "^7.7.1",
-    "execa": "^5.0.0",
+    "del": "^6.0.0",
+    "typescript": "^4.2.4",
     "xo": "^0.38.2"
   },
   "c8": {
@@ -34,7 +36,16 @@
       "text"
     ]
   },
+  "ava": {
+    "files": [
+      "!test/broken-fixtures/**"
+    ],
+    "timeout": "60s"
+  },
   "xo": {
+    "ignores": [
+      "test/broken-fixtures"
+    ],
     "rules": {
       "import/order": "off"
     }

test/_with-provider.js

@@ -0,0 +1,23 @@
+const path = require('path');
+const pkg = require('../package.json');
+const makeProvider = require('..');
+
+const createProviderMacro = (identifier, avaVersion, projectDir = __dirname) => {
+	return (t, run) => run(t, makeProvider({
+		negotiateProtocol(identifiers, {version}) {
+			t.true(identifiers.includes(identifier));
+			t.is(version, pkg.version);
+			return {
+				ava: {avaVersion},
+				identifier,
+				normalizeGlobPatterns: patterns => patterns,
+				async findFiles({patterns}) {
+					return patterns.map(file => path.join(projectDir, file));
+				},
+				projectDir
+			};
+		}
+	}));
+};
+
+module.exports = createProviderMacro;

test/broken-fixtures/tsconfig.json

@@ -0,0 +1,8 @@
+{
+	"compilerOptions": {
+		"outDir": "typescript/compiled"
+	},
+	"include": [
+		"typescript"
+	]
+}

test/broken-fixtures/typescript/typescript.ts

@@ -0,0 +1 @@
+a

test/compilation.js

@@ -0,0 +1,61 @@
+const path = require('path');
+const test = require('ava');
+const del = require('del');
+const execa = require('execa');
+const createProviderMacro = require('./_with-provider');
+
+const withProvider = createProviderMacro('ava-3.2', '3.2.0', path.join(__dirname, 'fixtures'));
+const withAltProvider = createProviderMacro('ava-3.2', '3.2.0', path.join(__dirname, 'broken-fixtures'));
+
+test.before('deleting compiled files', async t => {
+	t.log(await del('test/fixtures/typescript/compiled'));
+	t.log(await del('test/broken-fixtures/typescript/compiled'));
+});
+
+const compile = async provider => {
+	return {
+		state: await provider.main({
+			config: {
+				rewritePaths: {
+					'ts/': 'typescript/',
+					'compiled/': 'typescript/compiled/'
+				},
+				compile: 'tsc'
+			}
+		}).compile()
+	};
+};
+
+test('worker(): load rewritten paths files', withProvider, async (t, provider) => {
+	const {state} = await compile(provider);
+	const {stdout, stderr} = await execa.node(
+		path.join(__dirname, 'fixtures/install-and-load'),
+		[JSON.stringify(state), path.join(__dirname, 'fixtures/ts', 'file.ts')],
+		{cwd: path.join(__dirname, 'fixtures')}
+	);
+	if (stderr.length > 0) {
+		t.log(stderr);
+	}
+
+	t.snapshot(stdout);
+});
+
+test('worker(): runs compiled files', withProvider, async (t, provider) => {
+	const {state} = await compile(provider);
+	const {stdout, stderr} = await execa.node(
+		path.join(__dirname, 'fixtures/install-and-load'),
+		[JSON.stringify(state), path.join(__dirname, 'fixtures/compiled', 'index.ts')],
+		{cwd: path.join(__dirname, 'fixtures')}
+	);
+	if (stderr.length > 0) {
+		t.log(stderr);
+	}
+
+	t.snapshot(stdout);
+});
+
+test('compile() error', withAltProvider, async (t, provider) => {
+	const {message} = await t.throwsAsync(compile(provider));
+
+	t.snapshot(message);
+});

test/fixtures/install-and-load.js

@@ -3,16 +3,16 @@ const makeProvider = require('../..');
 
 const provider = makeProvider({
 	negotiateProtocol() {
-		return {identifier: process.argv[2], ava: {version: '3.0.0'}, projectDir: path.resolve(__dirname, '..')};
+		return {identifier: 'ava-3.2', ava: {version: '3.15.0'}, projectDir: __dirname};
 	}
 });
 
 const worker = provider.worker({
 	extensionsToLoadAsModules: [],
-	state: JSON.parse(process.argv[3])
+	state: JSON.parse(process.argv[2])
 });
 
-const ref = path.resolve(process.argv[4]);
+const ref = path.resolve(process.argv[3]);
 
 if (worker.canLoad(ref)) {
 	worker.load(ref, {requireFn: require});

test/fixtures/tsconfig.json

@@ -0,0 +1,8 @@
+{
+	"compilerOptions": {
+		"outDir": "typescript/compiled"
+	},
+	"include": [
+		"typescript"
+	]
+}

test/fixtures/typescript/index.ts

@@ -0,0 +1 @@
+console.log('logged in fixtures/typescript/index.ts');