feat(compiler): expose transformSync method (#1174)

* feat(compiler): add transform sync

* chore: remove deasync from jest

* chore: add tests for new API

* fix: fix typo in the test name

packages/@lwc/compiler/src/index.ts

@@ -5,5 +5,6 @@
  * For full license text, see the LICENSE file in the repo root or https://opensource.org/licenses/MIT
  */
 export { compile } from './compiler/compiler';
-export { transform } from './transformers/transformer';
+export { transform, transformSync } from './transformers/transformer';
+
 export const version = '__VERSION__';

packages/@lwc/compiler/src/rollup-plugins/transform.ts

@@ -6,7 +6,7 @@
  */
 import { Plugin } from 'rollup';
 
-import { getTransformer, FileTransformerResult } from '../transformers/transformer';
+import { transformFile } from '../transformers/transformer';
 
 import { NormalizedCompilerOptions } from '../compiler/options';
 import { MetadataCollector } from '../bundler/meta-collector';
@@ -20,9 +20,8 @@ export default function({
 }): Plugin {
     return {
         name: 'lwc-file-transform',
-        async transform(src: string, id: string): Promise<FileTransformerResult> {
-            const transform = getTransformer(id);
-            return await transform(src, id, options, metadataCollector);
+        transform(src: string, id: string) {
+            return transformFile(src, id, options, metadataCollector);
         },
     };
 }

packages/@lwc/compiler/src/transformers/__tests__/transform.spec.ts

@@ -4,16 +4,37 @@
  * SPDX-License-Identifier: MIT
  * For full license text, see the LICENSE file in the repo root or https://opensource.org/licenses/MIT
  */
-import { transform } from '../../transformers/transformer';
+import { transform, transformSync } from '../../transformers/transformer';
 
-const transformEntry: any = transform;
+function testValidateOptions(methodName, method) {
+    describe('validate options', () => {
+        it(`${methodName} should validate presence of src`, () => {
+            expect(() => method()).toThrow(/Expect a string for source. Received undefined/);
+        });
 
-it('should validate presence of src', () => {
-    expect(() => transformEntry()).toThrow(/Expect a string for source. Received undefined/);
+        it(`${methodName} should validate presence of filename`, () => {
+            expect(() => method(`console.log('Hello')`)).toThrow(
+                /Expect a string for id. Received undefined/
+            );
+        });
+    });
+}
+
+testValidateOptions('transform', transform);
+testValidateOptions('transformSync', transformSync);
+
+describe('transform', () => {
+    it('returns a promise resolving to an object with code', () => {
+        expect(transform(`console.log('Hello')`, 'foo.js', {})).resolves.toMatchObject({
+            code: expect.any(String),
+        });
+    });
 });
 
-it('should validate presence of id', () => {
-    expect(() => transformEntry(`console.log('Hello')`)).toThrow(
-        /Expect a string for id. Received undefined/
-    );
+describe('transformSync', () => {
+    it('returns to an object with code', () => {
+        expect(transformSync(`console.log('Hello')`, 'foo.js', {})).toMatchObject({
+            code: expect.any(String),
+        });
+    });
 });

packages/@lwc/compiler/src/transformers/javascript.ts

@@ -12,7 +12,7 @@ import { BABEL_CONFIG_BASE, BABEL_PLUGINS_BASE } from '../babel-plugins';
 import { NormalizedCompilerOptions } from '../compiler/options';
 import { FileTransformerResult } from './transformer';
 
-export default function(
+export default function scriptTransform(
     code: string,
     filename: string,
     options: NormalizedCompilerOptions

packages/@lwc/compiler/src/transformers/style.ts

@@ -9,7 +9,7 @@ import { normalizeToCompilerError, TransformerErrors } from '@lwc/errors';
 import { NormalizedCompilerOptions } from '../compiler/options';
 import { FileTransformerResult } from './transformer';
 
-export default function transformStyle(
+export default function styleTransform(
     src: string,
     filename: string,
     config: NormalizedCompilerOptions

packages/@lwc/compiler/src/transformers/template.ts

@@ -14,7 +14,6 @@ import {
 import compile from '@lwc/template-compiler';
 import { TemplateModuleDependency } from '@lwc/template-compiler';
 
-import { FileTransformer } from './transformer';
 import { MetadataCollector } from '../bundler/meta-collector';
 import { NormalizedCompilerOptions } from '../compiler/options';
 
@@ -31,7 +30,7 @@ export interface TemplateMetadata {
  * The transform also add a style import for the default stylesheet associated with
  * the template regardless if there is an actual style or not.
  */
-const transform: FileTransformer = function(
+export default function templateTransform(
     src: string,
     filename: string,
     options: NormalizedCompilerOptions,
@@ -67,7 +66,7 @@ const transform: FileTransformer = function(
         map: { mappings: '' },
         metadata,
     };
-};
+}
 
 function serialize(
     code: string,
@@ -94,5 +93,3 @@ function serialize(
 
     return buffer;
 }
-
-export default transform;

packages/@lwc/compiler/src/transformers/transformer.ts

@@ -11,60 +11,86 @@ import { NormalizedCompilerOptions, CompilerOptions, normalizeOptions } from '..
 
 import styleTransform from './style';
 import templateTransformer, { TemplateMetadata } from './template';
-import javascriptTransformer from './javascript';
+import scriptTransformer from './javascript';
 
 import { isString } from '../utils';
 import { MetadataCollector } from '../bundler/meta-collector';
 import { SourceMap } from '../compiler/compiler';
 
-// TODO: Improve on metadata type by providing consistent interface. Currently
-// javascript transformer output differs from css and html in that later return a promise
 export interface FileTransformerResult {
     code: string;
     metadata?: TemplateMetadata;
     map: SourceMap | null;
 }
 
-export type FileTransformer = (
-    source: string,
+/**
+ * Transforms the passed code. Returning a Promise of an object with the generated code, source map
+ * and gathered metadata.
+ *
+ * @deprecated Use transformSync instead.
+ */
+export function transform(
+    src: string,
     filename: string,
-    options: NormalizedCompilerOptions,
-    metadataCollector?: MetadataCollector
-) => FileTransformerResult | Promise<FileTransformerResult>;
+    options: CompilerOptions
+): Promise<FileTransformerResult> {
+    validateArguments(src, filename);
+    return new Promise((resolve, reject) => {
+        try {
+            const res = transformSync(src, filename, options);
+            resolve(res);
+        } catch (error) {
+            reject(error);
+        }
+    });
+}
 
-export function transform(src: string, id: string, options: CompilerOptions) {
-    invariant(isString(src), TransformerErrors.INVALID_SOURCE, [src]);
-    invariant(isString(id), TransformerErrors.INVALID_ID, [id]);
+/**
+ * Transform the passed source code. Returning an object with the generated code, source map and
+ * gathered metadata.
+ */
+export function transformSync(
+    src: string,
+    filename: string,
+    options: CompilerOptions
+): FileTransformerResult {
+    validateArguments(src, filename);
+    return transformFile(src, filename, normalizeOptions(options));
+}
 
-    return transformFile(src, id, normalizeOptions(options));
+function validateArguments(src: string, filename: string) {
+    invariant(isString(src), TransformerErrors.INVALID_SOURCE, [src]);
+    invariant(isString(filename), TransformerErrors.INVALID_ID, [filename]);
 }
 
-export function getTransformer(fileName: string): FileTransformer {
-    switch (path.extname(fileName)) {
+export function transformFile(
+    src: string,
+    filename: string,
+    options: NormalizedCompilerOptions,
+    metadataCollector?: MetadataCollector
+): FileTransformerResult {
+    let transformer;
+
+    switch (path.extname(filename)) {
         case '.html':
-            return templateTransformer;
+            transformer = templateTransformer;
+            break;
 
         case '.css':
-            return styleTransform;
+            transformer = styleTransform;
+            break;
 
         case '.ts':
         case '.js':
-            return javascriptTransformer;
+            transformer = scriptTransformer;
+            break;
 
         default:
             throw generateCompilerError(TransformerErrors.NO_AVAILABLE_TRANSFORMER, {
-                messageArgs: [fileName],
-                origin: { filename: fileName },
+                messageArgs: [filename],
+                origin: { filename },
             });
     }
-}
 
-export async function transformFile(
-    src: string,
-    id: string,
-    options: NormalizedCompilerOptions,
-    metadataCollector?: MetadataCollector
-): Promise<FileTransformerResult> {
-    const transformer = getTransformer(id);
-    return await transformer(src, id, options, metadataCollector);
+    return transformer(src, filename, options, metadataCollector);
 }

packages/@lwc/jest-transformer/package.json

@@ -16,8 +16,7 @@
         "@babel/plugin-transform-modules-commonjs": "7.1.0",
         "@babel/template": "~7.1.2",
         "@lwc/errors": "0.37.2",
-        "babel-preset-jest": "^24.0.0",
-        "deasync": "0.1.14"
+        "babel-preset-jest": "^24.0.0"
     },
     "peerDependencies": {
         "@lwc/compiler": "0.37.x",

packages/@lwc/jest-transformer/src/index.js

@@ -4,15 +4,17 @@
  * SPDX-License-Identifier: MIT
  * For full license text, see the LICENSE file in the repo root or https://opensource.org/licenses/MIT
  */
-const crypto = require('crypto');
 const path = require('path');
+const crypto = require('crypto');
+
 const babelCore = require('@babel/core');
-const babelCommonJs = require('@babel/plugin-transform-modules-commonjs');
-const jestPreset = require('babel-preset-jest');
 const lwcCompiler = require('@lwc/compiler');
+const jestPreset = require('babel-preset-jest');
+const babelCommonJs = require('@babel/plugin-transform-modules-commonjs');
+
 const engineVersion = require('@lwc/engine/package.json').version;
 const compilerVersion = require('@lwc/compiler/package.json').version;
-const { waitForPromise } = require('./utils');
+
 const apexScopedImport = require('./transforms/apex-scoped-import');
 const apexContinuationScopedImport = require('./transforms/apex-continuation-scoped-import');
 const i18nScopedImport = require('./transforms/i18n-scoped-import');
@@ -41,16 +43,14 @@ const BABEL_CONFIG = {
 module.exports = {
     process(src, filePath) {
         // Set default module name and namespace value for the namespace because it can't be properly guessed from the path
-        const transform = lwcCompiler.transform(src, filePath, {
+        const { code, map } = lwcCompiler.transformSync(src, filePath, {
             moduleName: 'test',
             moduleNamespace: 'x',
             outputConfig: {
                 sourcemap: true,
             },
         });
 
-        const { code, map } = waitForPromise(transform);
-
         // if is not .js, we add the .compiled extension in the sourcemap
         const filename = path.extname(filePath) === '.js' ? filePath : filePath + '.compiled';
         // **Note: .html and .css don't return valid sourcemaps cause they are used for rollup

yarn.lock

@@ -2261,11 +2261,6 @@ binary-extensions@^1.0.0:
   resolved "https://registry.yarnpkg.com/binary-extensions/-/binary-extensions-1.12.0.tgz#c2d780f53d45bba8317a8902d4ceeaf3a6385b14"
   integrity sha512-DYWGk01lDcxeS/K9IHPGWfT8PsJmbXRtRd2Sx72Tnb8pcYZQFF1oSDb8hJtS1vhp212q1Rzi5dUf9+nq0o9UIg==
 
-bindings@~1.2.1:
-  version "1.2.1"
-  resolved "https://registry.yarnpkg.com/bindings/-/bindings-1.2.1.tgz#14ad6113812d2d37d72e67b4cacb4bb726505f11"
-  integrity sha1-FK1hE4EtLTfXLme0ystLtyZQXxE=
-
 bl@^1.0.0:
   version "1.2.2"
   resolved "https://registry.yarnpkg.com/bl/-/bl-1.2.2.tgz#a160911717103c07410cef63ef51b397c025af9c"
@@ -3586,14 +3581,6 @@ dateformat@^3.0.0:
   resolved "https://registry.yarnpkg.com/dateformat/-/dateformat-3.0.3.tgz#a6e37499a4d9a9cf85ef5872044d62901c9889ae"
   integrity sha512-jyCETtSl3VMZMWeRo7iY1FL19ges1t55hMo5yaam4Jrsm5EPL89UQkoQRyiI+Yf4k8r2ZpdngkV8hr1lIdjb3Q==
 
-[email protected]:
-  version "0.1.14"
-  resolved "https://registry.yarnpkg.com/deasync/-/deasync-0.1.14.tgz#232ea2252b443948cad033d792eb3b24b0a3d828"
-  integrity sha512-wN8sIuEqIwyQh72AG7oY6YQODCxIp1eXzEZlZznBuwDF8Q03Tdy9QNp1BNZXeadXoklNrw+Ip1fch+KXo/+ASw==
-  dependencies:
-    bindings "~1.2.1"
-    node-addon-api "^1.6.0"
-
 [email protected], debug@^2.1.2, debug@^2.2.0, debug@^2.3.3, debug@~2.6.4:
   version "2.6.9"
   resolved "https://registry.yarnpkg.com/debug/-/debug-2.6.9.tgz#5d128515df134ff327e90a4c93f4e077a536341f"
@@ -7886,11 +7873,6 @@ nice-try@^1.0.4:
   resolved "https://registry.yarnpkg.com/nice-try/-/nice-try-1.0.5.tgz#a3378a7696ce7d223e88fc9b764bd7ef1089e366"
   integrity sha512-1nh45deeb5olNY7eX82BkPO7SSxR5SSYJiPTrTdFUVYwAl8CKMA5N9PjTYkHiRjisVcxcQ1HXdLhx2qxxJzLNQ==
 
-node-addon-api@^1.6.0:
-  version "1.6.2"
-  resolved "https://registry.yarnpkg.com/node-addon-api/-/node-addon-api-1.6.2.tgz#d8aad9781a5cfc4132cc2fecdbdd982534265217"
-  integrity sha512-479Bjw9nTE5DdBSZZWprFryHGjUaQC31y1wHo19We/k0BZlrmhqQitWoUL0cD8+scljCbIUL+E58oRDEakdGGA==
-
 node-fetch-npm@^2.0.2:
   version "2.0.2"
   resolved "https://registry.yarnpkg.com/node-fetch-npm/-/node-fetch-npm-2.0.2.tgz#7258c9046182dca345b4208eda918daf33697ff7"