feat: added support for watch mode

BREAKING CHANGE: The `options` parameter is now deprecated, the reason is that `exclude` and `include` do not make sense when importing the same asset from both excluded and included modules
recursive-beast · Mar 3, 2021 · f080246 · f080246
1 parent 730ac5b
commit f080246
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Showing 6 changed files with 37 additions and 119 deletions.
diff --git a/rollup.config.js b/rollup.config.js
@@ -23,6 +23,7 @@ export default {
 		// ...Object.keys(pkg.peerDependencies),
 		"fs",
 		"path",
+		"crypto",
 	],
 	plugins: [
 		nodeResolve(),

diff --git a/src/index.ts b/src/index.ts
@@ -1,26 +1,12 @@
 import fs from "fs";
 import path from "path";
+import crypto from "crypto";
 import { Plugin, OutputOptions } from "rollup";
 import { createFilter, FilterPattern } from "@rollup/pluginutils";
 import { parse, print, types, visit } from "recast";
 
-interface PluginOptions {
-	/**
-	 * A picomatch pattern, or array of patterns,
-	 * which correspond to modules the plugin should operate on.
-	 * By default all modules are targeted.
-	 */
-	include?: FilterPattern;
-	/**
-	 * A picomatch pattern, or array of patterns,
-	 * which correspond to modules the plugin should ignore.
-	 * By default no modules are ignored.
-	 */
-	exclude?: FilterPattern;
-}
-
 const PLUGIN_NAME = "external-assets";
-const REGEX_ESCAPED_PLUGIN_NAME = PLUGIN_NAME.replace(/[.*+?^${}()|[\]\\]/g, "\\$&");
+const PREFIX = `\0${PLUGIN_NAME}:`;
 
 function getOutputId(filename: string, outputOptions: OutputOptions) {
 	// Extract output directory from outputOptions.
@@ -52,102 +38,71 @@ function getRelativeImportPath(from: string, to: string) {
  * which correspond to assets the plugin should operate on.
  * @param options - The options object.
  */
-export default function externalAssets(pattern: FilterPattern, options?: PluginOptions): Plugin {
+export default function externalAssets(pattern: FilterPattern): Plugin {
 	if (!pattern) throw new Error("please specify a pattern for targeted assets");
 
-	const importerFilter = createFilter(options?.include, options?.exclude);
-	const sourceFilter = createFilter(pattern);
+	const idFilter = createFilter(pattern);
+	const hashToIdMap: Partial<Record<string, string>> = {};
 
 	return {
-		async buildStart() {
-			this.warn("'options' parameter is deprecated. Please update to the latest version.");
-		},
-
 		name: PLUGIN_NAME,
 
-		async options(inputOptions) {
-			const plugins = inputOptions.plugins;
-
-			// No transformations.
-			if (!plugins) return null;
-
-			// Separate our plugin from other plugins.
-			const externalAssetsPlugins: Plugin[] = [];
-			const otherPlugins = plugins.filter(plugin => {
-				if (plugin.name !== PLUGIN_NAME) return true;
-
-				externalAssetsPlugins.push(plugin);
-				return false;
-			});
+		async resolveId(source, importer) {
+			if (
+				!importer // Skip entrypoints.
+				|| !source.startsWith(PREFIX) // Not a hash that was calculated in the `load` hook.
+			) return null;
 
-			// Re-position our plugin to be the first in the list.
-			// Otherwise, if there's a plugin that resolves paths before ours,
-			// non-external imports can trigger the load hook for assets that can't be parsed by other plugins.
 			return {
-				...inputOptions,
-				plugins: [
-					...externalAssetsPlugins,
-					...otherPlugins,
-				],
+				id: source,
+				external: true
 			};
 		},
 
-		async resolveId(source, importer, options) {
-			// `this.resolve` was called from another instance of this plugin. skip to avoid infinite loop.
-			// or skip resolving entrypoints.
-			// or don't resolve imports from filtered out modules.
+		async load(id) {
 			if (
-				options.custom?.[PLUGIN_NAME]?.skip
-				|| !importer
-				|| !importerFilter(importer)
+				id.startsWith("\0") // Virtual module.
+				|| id.includes("?") // Id reserved by some other plugin.
+				|| !idFilter(id) // Filtered out id.
 			) return null;
 
-			// We'll delegate resolving to other plugins (alias, node-resolve ...),
-			// or eventually, rollup itself.
-			// We need to skip this plugin to avoid an infinite loop.
-			const resolution = await this.resolve(source, importer, {
-				skipSelf: true,
-				custom: {
-					[PLUGIN_NAME]: {
-						skip: true,
-					}
-				}
-			});
+			const hash = crypto.createHash('md5').update(id).digest('hex');
 
-			// If it cannot be resolved, or if the id is filtered out,
-			// return `null` so that Rollup displays an error.
-			if (!resolution || !sourceFilter(resolution.id)) return null;
+			// In the output phase,
+			// We'll use this mapping to replace the hash with a relative path from a chunk to the emitted asset.
+			hashToIdMap[hash] = id;
 
-			return {
-				...resolution,
-				// We'll need `target_id` to emit the asset in the output phase.
-				id: `${resolution.id}?${PLUGIN_NAME}&target_id=${resolution.id}`,
-				external: true,
-			};
+			// Load a proxy module with a hash as the import.
+			// The hash will be resolved as external.
+			// The benefit of doing it this way, instead of resolving asset imports to external ids,
+			// is that we get watch mode support out of the box.
+			return `export * from "${PREFIX + hash}";\n`
+				+ `export { default } from "${PREFIX + hash}";\n`;
 		},
 
 		async renderChunk(code, chunk, outputOptions) {
 			const chunk_id = getOutputId(chunk.fileName, outputOptions);
 			const chunk_basename = path.basename(chunk_id);
 
 			const ast = parse(code, { sourceFileName: chunk_basename });
-			const pattern = new RegExp(`.+\\?${REGEX_ESCAPED_PLUGIN_NAME}&target_id=(.+)`);
 			const rollup_context = this;
 
 			visit(ast, {
 				visitLiteral(nodePath) {
-					const node = nodePath.node;
+					const value = nodePath.node.value;
 
-					// We're only concerned with string literals.
-					if (typeof node.value !== "string") return this.traverse(nodePath);
+					if (
+						typeof value !== "string" // We're only concerned with string literals.
+						|| !value.startsWith(PREFIX) // Not a hash that was calculated in the `load` hook.
+					) return this.traverse(nodePath);
 
-					const match = node.value.match(pattern);
+					const hash = value.slice(PREFIX.length);
+					const target_id = hashToIdMap[hash];
 
-					// This string does not refer to an import path that we resolved in the `resolveId` hook.
-					if (!match) return this.traverse(nodePath);
+					// The hash belongs to another instance of this plugin.
+					if (!target_id) return this.traverse(nodePath);
 
 					// Emit the targeted asset.
-					const target_id = match[1];
 					const asset_reference_id = rollup_context.emitFile({
 						type: "asset",
 						source: fs.readFileSync(target_id),

diff --git a/tests/general.test.js b/tests/general.test.js
@@ -1,6 +1,5 @@
 const test = require("ava");
 const { nodeResolve } = require("@rollup/plugin-node-resolve");
-const { rollup } = require("rollup");
 const { outputSnapshotMacro } = require("./macros");
 const externalAssets = require("..");
 
@@ -16,21 +15,6 @@ for (const value of falsy) {
 	});
 }
 
-// Solved by re-positioning the plugin to be the first on the list.
-test("Plugin works even if it's not the first in the list", async t => {
-	await t.notThrowsAsync(
-		rollup({
-			input: "tests/fixtures/src/index2.js",
-			plugins: [
-				nodeResolve({
-					moduleDirectories: ["tests/fixtures/node_modules"],
-				}),
-				externalAssets(["tests/fixtures/assets/*", /@fontsource\/open-sans/]),
-			],
-		})
-	);
-});
-
 test("Multiple instances of the plugin can be used at the same time", outputSnapshotMacro,
 	{
 		input: "tests/fixtures/src/index2.js",

diff --git a/tests/resolve.test.js b/tests/resolve.test.js
@@ -1,5 +1,4 @@
 const test = require("ava");
-const { rollup } = require("rollup");
 const { outputSnapshotMacro } = require("./macros");
 const { nodeResolve } = require("@rollup/plugin-node-resolve");
 const alias = require("@rollup/plugin-alias");
@@ -12,27 +11,6 @@ test("Skips resolving entrypoints", async t => {
 	t.is(resolution, null);
 });
 
-// Rollup will not be able to parse assets imported from excluded modules.
-test("Doesn't process imports from excluded modules", async t => {
-	await t.throwsAsync(
-		rollup({
-			input: "tests/fixtures/src/index1.js",
-			plugins: [
-				externalAssets(
-					"tests/fixtures/assets/*",
-					{
-						exclude: /1\.js$/,
-						include: "tests/fixtures/src/*.js",
-					}
-				),
-			],
-		}),
-		{
-			code: "PARSE_ERROR",
-		}
-	);
-});
-
 test(`Resolve with @rollup/plugin-node-resolve`, outputSnapshotMacro,
 	{
 		input: "tests/fixtures/src/index2.js",

diff --git a/tests/snapshots/output.test.js.md b/tests/snapshots/output.test.js.md
@@ -10895,7 +10895,7 @@ Generated by [AVA](https://avajs.dev).
 
     [
       {
-        code: `define(["./assets/image-0fc60877.png", "./assets/text-6d7076f2.txt", "./assets/styles-fc0ceb37.css"], function (png, text, styles_css) { 'use strict';␊
+        code: `define(["./assets/image-0fc60877.png", "./assets/text-6d7076f2.txt", "./assets/styles-fc0ceb37.css"], function (png, text, _externalAssets_4310739eb4843f3840c8bd0630aa60b0) { 'use strict';␊
         ␊
         	function _interopDefaultLegacy (e) { return e && typeof e === 'object' && 'default' in e ? e : { 'default': e }; }␊
         ␊

diff --git a/tests/snapshots/output.test.js.snap b/tests/snapshots/output.test.js.snap