refactor: delegate asset deduplication to this.emitFile

BREAKING CHANGE: imports to deduplicated assets are not merged into one

Author: recursive-beast

src/helpers.ts

@@ -1,6 +1,4 @@
-import fs from "fs";
 import path from "path";
-import crypto from "crypto";
 import { OutputOptions } from "rollup";
 
 export function getOutputId(filename: string, outputOptions: OutputOptions) {
@@ -26,28 +24,3 @@ export function getRelativeImportPath(from: string, to: string) {
 
 	return import_path;
 }
-
-export function getContentHash(filepath: string) {
-	const md5sum = crypto.createHash("md5");
-
-	return new Promise<string>((resolve, reject) =>
-		fs.createReadStream(filepath)
-			.on("data", chunk => md5sum.update(chunk))
-			.on("end", () => resolve(md5sum.digest("hex")))
-			.on("error", err => reject(err))
-	);
-}
-
-export function getIdDeduplicator() {
-	const hashToIdMap: Record<string, string | undefined> = {};
-
-	return async (id: string) => {
-		const hash = await getContentHash(id);
-		let result = hashToIdMap[hash];
-
-		if (result) return result;
-
-		hashToIdMap[hash] = id;
-		return id;
-	}
-}

src/index.ts

@@ -3,7 +3,7 @@ import path from "path";
 import { Plugin } from "rollup";
 import { createFilter, FilterPattern } from "@rollup/pluginutils";
 import { parse, print, types, visit } from "recast";
-import { getIdDeduplicator, getOutputId, getRelativeImportPath } from "./helpers";
+import { getOutputId, getRelativeImportPath } from "./helpers";
 
 const PLUGIN_NAME = "external-assets";
 const PREFIX = `\0${PLUGIN_NAME}:`;
@@ -36,7 +36,6 @@ export default function externalAssets(
 ): Plugin {
 	const idFilter = createFilter(include, exclude, options);
 	const assets = new Map<string, Buffer>();
-	const deduplicateId = getIdDeduplicator();
 
 	return {
 		name: PLUGIN_NAME,
@@ -57,10 +56,6 @@ export default function externalAssets(
 		async load(id) {
 			if (!idFilter(id)) return null;
 
-			// For two or more assets with the same content, only one asset is going to be emitted.
-			// `this.emitFile` deduplicates in the same way.
-			id = await deduplicateId(id);
-
 			assets.set(id, await fs.readFile(id));
 
 			// Load a proxy module that rollup will discard in favor of inligning the imports.

tests/__snapshots__/output.test.ts.snap

@@ -1,9 +1,10 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
 exports[`deduplicate assets with different names: index6 1`] = `
-"import png from \\"./assets/image2-479dcdf1.png\\";
+"import png from \\"./assets/image-0fc60877.png\\";
 import text from \\"./assets/text-6d7076f2.txt\\";
 import \\"./assets/styles-fc0ceb37.css\\";
+import png2 from \\"./assets/image-0fc60877.png\\";
 
 // This import should not be removed unless specified by the user or some other plugin.
 
@@ -17,7 +18,7 @@ var main = () => {
 	sayHi();
 };
 
-console.log(png);
+console.log(png2);
 main();
 "
 `;

tests/unit.test.ts

@@ -1,23 +1,5 @@
 import path from "path";
-import {
-	getOutputId,
-	getIdDeduplicator,
-} from "../src/helpers";
-
-test("getIdDeduplicator", async () => {
-	const deduplicateId = getIdDeduplicator();
-
-	const image = path.resolve("tests/fixtures/assets/image.png");
-	const image2 = path.resolve("tests/fixtures/assets/image2.png");
-	const text = path.resolve("tests/fixtures/assets/text.txt");
-
-	expect(async () => await deduplicateId("/non/existent/path")).rejects.toThrow();
-	expect(await deduplicateId(image)).toBe(image);
-	expect(await deduplicateId(text)).toBe(text);
-	expect(await deduplicateId(image2)).toBe(image);
-	expect(await deduplicateId(image)).toBe(image);
-	expect(await deduplicateId(image2)).toBe(image);
-});
+import { getOutputId } from "../src/helpers";
 
 test("getOutputId", () => {
 	expect(getOutputId("a.ext", { dir: "out" })).toBe(path.resolve("out/a.ext"));