♻️ Support absolute import paths

build-system/babel-config/helpers.js

@@ -137,8 +137,26 @@ function getReplaceGlobalsPlugin() {
   ];
 }
 
+/**
+ * Plugin config for import mapping (in compilation only, not browser).
+ * @return {!Array<string|Object>}
+ */
+function getImportResolverPlugin() {
+  return [
+    'module-resolver',
+    {
+      'root': ['.'],
+      'alias': {
+        '@': '.',
+        '@@': './src/core',
+      },
+    },
+  ];
+}
+
 module.exports = {
   getExperimentConstant,
   getReplacePlugin,
   getReplaceGlobalsPlugin,
+  getImportResolverPlugin,
 };

build-system/babel-config/minified-config.js

@@ -16,6 +16,7 @@
 'use strict';
 
 const argv = require('minimist')(process.argv.slice(2));
+const {getImportResolverPlugin} = require('./helpers');
 const {getReplacePlugin} = require('./helpers');
 
 /**
@@ -36,6 +37,7 @@ function getMinifiedConfig() {
 
   const plugins = [
     'optimize-objstr',
+    getImportResolverPlugin(),
     './build-system/babel-plugins/babel-plugin-transform-fix-leading-comments',
     './build-system/babel-plugins/babel-plugin-transform-promise-resolve',
     '@babel/plugin-transform-react-constant-elements',

build-system/babel-config/pre-closure-config.js

@@ -16,6 +16,7 @@
 'use strict';
 
 const argv = require('minimist')(process.argv.slice(2));
+const {getImportResolverPlugin} = require('./helpers');
 const {getReplacePlugin} = require('./helpers');
 
 /**
@@ -40,6 +41,7 @@ function getPreClosureConfig() {
   const replacePlugin = getReplacePlugin();
   const preClosurePlugins = [
     'optimize-objstr',
+    getImportResolverPlugin(),
     argv.coverage ? 'babel-plugin-istanbul' : null,
     './build-system/babel-plugins/babel-plugin-transform-fix-leading-comments',
     './build-system/babel-plugins/babel-plugin-transform-promise-resolve',

build-system/babel-config/test-config.js

@@ -16,6 +16,7 @@
 'use strict';
 
 const argv = require('minimist')(process.argv.slice(2));
+const {getImportResolverPlugin} = require('./helpers');
 const {getReplacePlugin, getReplaceGlobalsPlugin} = require('./helpers');
 
 /**
@@ -57,6 +58,7 @@ function getTestConfig() {
   const replacePlugin = getReplacePlugin();
   const replaceGlobalsPlugin = getReplaceGlobalsPlugin();
   const testPlugins = [
+    getImportResolverPlugin(),
     argv.coverage ? instanbulPlugin : null,
     replacePlugin,
     replaceGlobalsPlugin,

build-system/babel-config/unminified-config.js

@@ -19,6 +19,7 @@ const argv = require('minimist')(process.argv.slice(2));
 const {
   VERSION: internalRuntimeVersion,
 } = require('../compile/internal-version');
+const {getImportResolverPlugin} = require('./helpers');
 const {getReplacePlugin} = require('./helpers');
 
 /**
@@ -49,6 +50,7 @@ function getUnminifiedConfig() {
   ];
   const replacePlugin = getReplacePlugin();
   const unminifiedPlugins = [
+    getImportResolverPlugin(),
     argv.coverage ? 'babel-plugin-istanbul' : null,
     replacePlugin,
     './build-system/babel-plugins/babel-plugin-transform-json-import',

build-system/tasks/storybook/amp-env/webpack.config.js

@@ -27,6 +27,10 @@ module.exports = ({config}) => {
       path.join(__dirname, '../node_modules'),
       path.join(__dirname, '../../../../node_modules'),
     ],
+    alias: {
+      '@': path.join(__dirname, '../../../..'),
+      '@@': path.join(__dirname, '../../../../src/core'),
+    },
   };
   config.module = {
     rules: [

build-system/tasks/storybook/preact-env/webpack.config.js

@@ -31,6 +31,8 @@ module.exports = ({config}) => {
     alias: {
       'react': 'preact/compat',
       'react-dom': 'preact/compat',
+      '@': path.join(__dirname, '../../../..'),
+      '@@': path.join(__dirname, '../../../../src/core'),
     },
   };
   config.module = {

jsconfig.json

@@ -0,0 +1,9 @@
+{
+  "compilerOptions": {
+    "baseUrl": ".",
+    "paths": {
+      "@/*": ["./*"],
+      "@@/*": ["./src/core/*"]
+    }
+  }
+}

package.json

@@ -67,6 +67,7 @@
     "ava": "3.15.0",
     "babel-plugin-istanbul": "6.0.0",
     "babel-plugin-minify-replace": "0.5.0",
+    "babel-plugin-module-resolver": "4.1.0",
     "babel-plugin-optimize-objstr": "1.0.0",
     "baconipsum": "0.1.2",
     "base62": "2.0.1",

src/core/assert/base.js

@@ -14,10 +14,10 @@
  * limitations under the License.
  */
 
-import {elementStringOrPassThru} from '../error-message-helpers';
-import {includes} from '../types/string';
-import {isArray, isElement, isEnumValue, isString} from '../types';
-import {remove} from '../types/array';
+import {elementStringOrPassThru} from '@@/error-message-helpers';
+import {includes} from '@@/types/string';
+import {isArray, isElement, isEnumValue, isString} from '@@/types';
+import {remove} from '@@/types/array';
 
 /**
  * @fileoverview This file provides the base implementation for assertion

src/core/assert/dev.js

@@ -15,7 +15,7 @@
  */
 
 import * as assertions from './base';
-import {isMinifiedMode} from '../minified-mode';
+import {isMinifiedMode} from '@@/minified-mode';
 
 /**
  * @fileoverview This file provides the entrypoint for dev assertions. It's

src/core/assert/user.js

@@ -30,7 +30,7 @@
  */
 
 import * as assertions from './base';
-import {USER_ERROR_SENTINEL} from '../error-message-helpers';
+import {USER_ERROR_SENTINEL} from '@@/error-message-helpers';
 
 /**
  * @fileoverview This file provides the entrypoint for user assertions. It's

src/core/constants/action-constants.js

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-import {pureDevAssert as devAssert} from '../assert';
+import {pureDevAssert as devAssert} from '@@/assert';
 
 /**
  * Key string in an action arguments map for an unparsed object literal string.

src/core/data-structures/signals.js

@@ -14,8 +14,8 @@
  * limitations under the License.
  */
 
-import {Deferred} from './promise';
-import {map} from '../types/object';
+import {Deferred} from '@@/data-structures/promise';
+import {map} from '@@/types/object';
 
 /**
  * This object tracts signals and allows blocking until a signal has been

src/core/dom/css.js

@@ -15,7 +15,7 @@
  */
 
 import {cssEscape} from '../../../third_party/css-escape/css-escape';
-import {pureDevAssert as devAssert} from '../assert';
+import {pureDevAssert as devAssert} from '@@/assert';
 
 /**
  * @type {boolean|undefined}

src/core/error-message-helpers.js

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-import {isElement} from './types';
+import {isElement} from '@@/types';
 
 /**
  * Triple zero width space.

test/unit/core/data-structures/test-lru-cache.js

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-import {LruCache} from '../../../../src/core/data-structures/lru-cache';
+import {LruCache} from '@@/data-structures/lru-cache';
 
 describes.sandboxed('LruCache', {}, () => {
   let cache;

test/unit/core/data-structures/test-observable.js

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-import {Observable} from '../../../../src/core/data-structures/observable';
+import {Observable} from '@@/data-structures/observable';
 
 describes.sandboxed('Observable', {}, () => {
   let observable;

test/unit/core/data-structures/test-priority-queue.js

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-import PriorityQueue from '../../../../src/core/data-structures/priority-queue';
+import PriorityQueue from '@@/data-structures/priority-queue';
 
 describes.sandboxed('PriorityQueue', {}, () => {
   let pq;

test/unit/core/data-structures/test-promise.js

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-import * as PromiseUtils from '../../../../src/core/data-structures/promise';
+import * as PromiseUtils from '@@/data-structures/promise';
 
 describes.sandboxed('PromiseUtils', {}, () => {
   function getPromiseObject() {

test/unit/core/data-structures/test-signals.js

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-import {Signals} from '../../../../src/core/data-structures/signals';
+import {Signals} from '@@/data-structures/signals';
 
 describes.sandboxed('Signals', {}, (env) => {
   let clock;

test/unit/core/dom/test-css.js

@@ -14,10 +14,7 @@
  * limitations under the License.
  */
 
-import {
-  escapeCssSelectorIdent,
-  prependSelectorsWith,
-} from '../../../../src/core/dom/css';
+import {escapeCssSelectorIdent, prependSelectorsWith} from '@@/dom/css';
 
 describes.sandboxed('CSS', {}, () => {
   describe('escapeCssSelectorIdent', () => {

test/unit/core/test-assert.js

@@ -14,11 +14,11 @@
  * limitations under the License.
  */
 
-import {USER_ERROR_SENTINEL} from '../../../src/core/error-message-helpers';
+import {USER_ERROR_SENTINEL} from '@@/error-message-helpers';
 import {
   pureDevAssert as devAssert,
   pureUserAssert as userAssert,
-} from '../../../src/core/assert';
+} from '@@/assert';
 
 describes.sandboxed('assertions', {}, () => {
   describe('devAssert', () => {

test/unit/core/test-error.js

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-import {duplicateErrorIfNecessary, rethrowAsync} from '../../../src/core/error';
+import {duplicateErrorIfNecessary, rethrowAsync} from '@@/error';
 import {isUserErrorMessage, user} from '../../../src/log';
 
 describes.sandboxed('errors', {}, () => {