feat(@angular-devkit/build-angular): support package references in styles & scripts options

The browser builder's `styles` and `scripts` options now support using a package name in the path when specifying a style or script.  This removes the need to use a relative path to the node modules directory in these options.  This provides support for Yarn PnP as well as reducing the complexity of the options especially for monorepo setups.  Relatively located files will take precedence over packages if they exist.  This precedence provides backwards compatibility with existing configurations.

Before :
`"styles": ["../node_modules/bootstrap/dist/css/bootstrap.css"]`

After:
`"styles": ["bootstrap/dist/css/bootstrap.css"]`

Author: clydin

packages/angular_devkit/build_angular/src/browser/specs/styles_spec.ts

@@ -570,7 +570,7 @@ describe('Browser Builder styles', () => {
     expect(main).toContain(`url('/base/assets/component-img-absolute.svg')`);
   }, 90000);
 
-  it(`supports bootstrap@4`, async () => {
+  it(`supports bootstrap@4 with full path`, async () => {
     const bootstrapPath = dirname(require.resolve('bootstrap/package.json'));
 
     const overrides = {
@@ -582,6 +582,16 @@ describe('Browser Builder styles', () => {
     await browserBuild(architect, host, target, overrides);
   });
 
+  it(`supports bootstrap@4 with package reference`, async () => {
+    const overrides = {
+      extractCss: true,
+      styles: ['bootstrap/dist/css/bootstrap.css'],
+      scripts: ['bootstrap/dist/js/bootstrap.js'],
+    };
+
+    await browserBuild(architect, host, target, overrides);
+  });
+
   it(`supports inline javascript in less`, async () => {
     const overrides = { styles: [`src/styles.less`] };
     host.writeMultipleFiles({

packages/angular_devkit/build_angular/src/dev-server/index.ts

@@ -569,7 +569,16 @@ function _addLiveReload(
       // When HMR is enabled we need to add the css paths as part of the entrypoints
       // because otherwise no JS bundle will contain the HMR accept code.
       const normalizedStyles = normalizeExtraEntryPoints(browserOptions.styles, 'styles')
-        .map(style => path.resolve(root, style.input));
+        .map(style => {
+          let resolvedPath = path.resolve(root, style.input);
+          if (!existsSync(resolvedPath)) {
+            try {
+              resolvedPath = require.resolve(style.input, { paths: [root] });
+            } catch {}
+          }
+
+          return resolvedPath;
+        });
       entryPoints.push(...normalizedStyles);
     }
 

packages/angular_devkit/build_angular/src/webpack/configs/common.ts

@@ -208,10 +208,14 @@ export function getCommonConfig(wco: WebpackConfigOptions): Configuration {
     'scripts',
   ).reduce((prev: { bundleName: string; paths: string[]; inject: boolean }[], curr) => {
     const { bundleName, inject, input } = curr;
-    const resolvedPath = path.resolve(root, input);
+    let resolvedPath = path.resolve(root, input);
 
     if (!existsSync(resolvedPath)) {
-      throw new Error(`Script file ${input} does not exist.`);
+      try {
+        resolvedPath = require.resolve(input, { paths: [root] });
+      } catch {
+        throw new Error(`Script file ${input} does not exist.`);
+      }
     }
 
     const existingEntry = prev.find(el => el.bundleName === bundleName);

packages/angular_devkit/build_angular/src/webpack/configs/styles.ts

@@ -7,6 +7,7 @@
  */
 
 import { tags } from '@angular-devkit/core';
+import * as fs from 'fs';
 import * as path from 'path';
 import * as webpack from 'webpack';
 import { WebpackConfigOptions } from '../../utils/build-options';
@@ -58,7 +59,12 @@ export function getStylesConfig(wco: WebpackConfigOptions) {
     const chunkNames: string[] = [];
 
     normalizeExtraEntryPoints(buildOptions.styles, 'styles').forEach(style => {
-      const resolvedPath = path.resolve(root, style.input);
+      let resolvedPath = path.resolve(root, style.input);
+      if (!fs.existsSync(resolvedPath)) {
+        try {
+          resolvedPath = require.resolve(style.input, { paths: [root] });
+        } catch {}
+      }
       // Add style entry points.
       if (entryPoints[style.bundleName]) {
         entryPoints[style.bundleName].push(resolvedPath);