polyfills-loader - npm Package Compare versions

Comparing version 1.3.1 to 1.4.0

CHANGELOG.md

@@ -6,2 +6,13 @@ # Change Log
 
+# [1.4.0](https://github.com/open-wc/open-wc/compare/polyfills-loader@1.3.1...polyfills-loader@1.4.0) (2020-03-08)
+
+
+### Features
+
+* **polyfills-loader:** add preload links ([23428e3](https://github.com/open-wc/open-wc/commit/23428e344154af6826e7db6a72f67533f3bd9511))
+
+
+
+
+
 ## [1.3.1](https://github.com/open-wc/open-wc/compare/polyfills-loader@1.3.0...polyfills-loader@1.3.1) (2020-03-06)
@@ -8,0 +19,0 @@

package.json

 {
   "name": "polyfills-loader",
-  "version": "1.3.1",
+  "version": "1.4.0",
   "publishConfig": {
@@ -54,3 +54,3 @@ "access": "public"
   },
-  "gitHead": "d91e325385b15637e49b4231ab17972cf4e7555f"
+  "gitHead": "f58e5d4852e63244eeacc1f524894e18efac3915"
 }

src/inject-polyfills-loader.js

 /** @typedef {import('parse5').Document} DocumentAst */
 /** @typedef {import('./types').PolyfillsLoaderConfig} PolyfillsLoaderConfig */
+/** @typedef {import('./types').PolyfillsLoader} PolyfillsLoader */
 /** @typedef {import('./types').GeneratedFile} GeneratedFile */
@@ -14,3 +15,3 @@
 } = require('@open-wc/building-utils/dom5-fork');
-const { createScript, findImportMapScripts } = require('@open-wc/building-utils');
+const { createScript, createElement, findImportMapScripts } = require('@open-wc/building-utils');
 const { createPolyfillsLoader } = require('./create-polyfills-loader');
@@ -60,2 +61,35 @@ const { hasFileOfType, fileTypes } = require('./utils');
 /**
+ * @param {*} bodyAst
+ * @param {PolyfillsLoader} polyfillsLoader
+ */
+function injectLoaderScript(bodyAst, polyfillsLoader) {
+  const loaderScript = createScript({}, polyfillsLoader.code);
+  append(bodyAst, loaderScript);
+}
+
+/**
+ * @param {any} headAst
+ * @param {PolyfillsLoaderConfig} cfg
+ */
+function injectPrefetchLinks(headAst, cfg) {
+  for (const file of cfg.modern.files) {
+    const { path } = file;
+    const href = path.startsWith('.') || path.startsWith('/') ? path : `./${path}`;
+    if ([fileTypes.MODULE, fileTypes.ES_MODULE_SHIMS].includes(file.type)) {
+      append(
+        headAst,
+        createElement('link', {
+          rel: 'preload',
+          href,
+          as: 'script',
+          crossorigin: 'anonymous',
+        }),
+      );
+    } else {
+      append(headAst, createElement('link', { rel: 'preload', href, as: 'script' }));
+    }
+  }
+}
+
+/**
  * Transforms an index.html file, injecting a polyfills loader for
@@ -84,6 +118,7 @@ * compatibility with older browsers.
 
-  const loaderScript = createScript({}, polyfillsLoader.code);
-  append(bodyAst, loaderScript);
-
+  if (cfg.preload) {
+    injectPrefetchLinks(headAst, cfg);
+  }
   injectImportMapPolyfills(documentAst, headAst, cfg);
+  injectLoaderScript(bodyAst, polyfillsLoader);
 
@@ -90,0 +125,0 @@ return {

src/types.d.ts

@@ -17,2 +17,5 @@ export interface PolyfillsLoaderConfig {
   minify?: boolean;
+  // whether to preload the modern entrypoint, best for performance
+  // defaults to true
+  preload?: boolean;
 }
@@ -19,0 +22,0 @@

No alert changes

Improved metrics

Total package byte prevSize

42735

3.27%

Lines of code

732

5.32%

No dependency changes