perf: validate options with a precompiled check

.changeset/precompiled-options-check.md

@@ -0,0 +1,5 @@
+---
+"minimizer-webpack-plugin": patch
+---
+
+perf: validate options with a check precompiled by `schema-utils precompile`, so valid options no longer load `ajv` and compile the schema, about 200ms off every production webpack start

.cspell.json

@@ -80,6 +80,7 @@
     "CHANGELOG.md",
     "package.json",
     "src/serialize-javascript.js",
+    "src/options.check.js",
     "dist/**",
     "**/__snapshots__/**",
     "package-lock.json",

.prettierignore

@@ -1,4 +1,5 @@
 src/serialize-javascript.js
+src/options.check.js
 /coverage
 /dist
 /node_modules

babel.config.js

@@ -5,6 +5,9 @@ module.exports = (api) => {
   api.cache(true);
 
   return {
+    // Generated by `schema-utils precompile` for Node.js 10.13.0 already, so it
+    // is copied as is rather than grown three times by the transforms
+    ignore: ["src/options.check.js"],
     presets: [
       [
         "@babel/preset-env",

eslint.config.mjs

@@ -2,6 +2,8 @@ import { defineConfig } from "eslint/config";
 import configs from "eslint-config-webpack/configs.js";
 
 export default defineConfig([
+  // Generated by `schema-utils precompile`, `npm run fix:schema` updates it
+  { ignores: ["src/options.check.js"] },
   {
     ignores: ["./src/serialize-javascript.js"],
     extends: [configs["recommended-dirty"]],

jest.config.js

@@ -37,7 +37,15 @@ module.exports = {
   // older Node on macOS), where webpack + multiple minimizers per asset
   // routinely take longer than that.
   testTimeout: 60000,
-  coveragePathIgnorePatterns: ["src/serialize-javascript.js"],
+  coveragePathIgnorePatterns: [
+    "src/serialize-javascript.js",
+    "src/options.check.js",
+  ],
+  // Babel ignores the generated check, see `babel.config.js`
+  transformIgnorePatterns: [
+    "/node_modules/",
+    "<rootDir>/src/options\\.check\\.js$",
+  ],
   snapshotSerializers: ["<rootDir>/test/helpers/snapshotHashSerializer.js"],
   testPathIgnorePatterns,
 };

package.json

@@ -63,14 +63,16 @@
     "build": "npm-run-all -p \"build:**\"",
     "security": "npm audit --production",
     "lint:serialize-javascript": "node ./scripts/copy-serialize-javascript.js --check",
+    "lint:schema": "schema-utils precompile --check src/options.json",
     "lint:prettier": "prettier --list-different .",
     "lint:code": "eslint --cache .",
     "lint:spelling": "cspell \"**/*.*\"",
     "lint:types": "tsc --pretty --noEmit",
     "lint": "npm-run-all -l -p \"lint:**\"",
     "fix:code": "npm run lint:code -- --fix",
     "fix:prettier": "npm run lint:prettier -- --write",
-    "fix": "npm-run-all -l fix:code fix:prettier",
+    "fix:schema": "schema-utils precompile src/options.json",
+    "fix": "npm-run-all -l fix:schema fix:code fix:prettier",
     "test:base": "node ./scripts/jest.js",
     "test:watch": "npm run test:base -- --watch",
     "test:coverage": "npm run test:base -- --collectCoverageFrom=\"src/**/*.js\" --coverage",
@@ -83,7 +85,7 @@
   "dependencies": {
     "@jridgewell/trace-mapping": "^0.3.31",
     "jest-worker": "^27.4.5",
-    "schema-utils": "^4.3.3",
+    "schema-utils": "^4.6.0",
     "terser": "^5.51.0"
   },
   "devDependencies": {

src/index.js

@@ -2413,10 +2413,13 @@ class MinimizerPlugin {
    */
   validateOptions(compiler) {
     if (typeof compiler.validate === "function") {
+      // The precompiled check validates valid options without `ajv`, webpack
+      // only compiles the schema to report what is wrong with invalid ones
       compiler.validate(
         () => /** @type {Schema} */ (require("./options.json")),
         this.rawOptions,
         VALIDATION_CONFIGURATION,
+        require("./options.check.js"),
       );
       this.validateMinimizers();
       this.validateGenerators();
@@ -2432,6 +2435,7 @@ class MinimizerPlugin {
       /** @type {Schema} */ (require("./options.json")),
       this.rawOptions,
       VALIDATION_CONFIGURATION,
+      require("./options.check.js"),
     );
     this.validateMinimizers();
     this.validateGenerators();

test/__snapshots__/validate-options.test.js.snap

@@ -127,22 +127,22 @@ exports[`validation validate 8`] = `
 exports[`validation validate 9`] = `
 "Invalid options object. Minimizer Plugin has been initialized using an options object that does not match the API schema.
  - options.minify should be one of these:
-   function | non-empty string | object { path, export? } | [function | non-empty string | object { path, export? } | object { implementation, options?, filter? }, ...] | object { implementation, options?, filter? }
+   function | non-empty string | object { path: non-empty string, export?: non-empty string } | [function | non-empty string | object { path: non-empty string, export?: non-empty string } | object { implementation, options?, filter?: function }, ...] | object { implementation, options?, filter?: function }
    -> Allows you to override default minify function. Written as an object it states how to run one minimizer, options included. An empty array is no minimizers at all, for an instance whose whole job is its \`generate\`. A string or \`{ path, export }\` loads the minimizer by module path in workers (like sass-loader \`implementation\`).
    -> Read more at https://github.com/webpack/minimizer-webpack-plugin#number
    Details:
     * options.minify should be one of these:
-      function | non-empty string | object { path, export? }
+      function | non-empty string | object { path: non-empty string, export?: non-empty string }
       -> The minimizer itself: a function, a module path string (worker \`require\`s it), or \`{ path, export }\` for a named export.
       Details:
        * options.minify should be an instance of function.
        * options.minify should be a non-empty string.
        * options.minify should be an object:
-         object { path, export? }
+         object { path: non-empty string, export?: non-empty string }
     * options.minify should be an array:
-      [function | non-empty string | object { path, export? } | object { implementation, options?, filter? }, ...]
+      [function | non-empty string | object { path: non-empty string, export?: non-empty string } | object { implementation, options?, filter?: function }, ...]
     * options.minify should be an object:
-      object { implementation, options?, filter? }"
+      object { implementation, options?, filter?: function }"
 `;
 
 exports[`validation validate 10`] = `
@@ -247,20 +247,20 @@ exports[`validation validate 18`] = `
 exports[`validation validate 19`] = `
 "Invalid options object. Minimizer Plugin has been initialized using an options object that does not match the API schema.
  - options.minify should be one of these:
-   function | non-empty string | object { path, export? } | [function | non-empty string | object { path, export? } | object { implementation, options?, filter? }, ...] | object { implementation, options?, filter? }
+   function | non-empty string | object { path: non-empty string, export?: non-empty string } | [function | non-empty string | object { path: non-empty string, export?: non-empty string } | object { implementation, options?, filter?: function }, ...] | object { implementation, options?, filter?: function }
    -> Allows you to override default minify function. Written as an object it states how to run one minimizer, options included. An empty array is no minimizers at all, for an instance whose whole job is its \`generate\`. A string or \`{ path, export }\` loads the minimizer by module path in workers (like sass-loader \`implementation\`).
    -> Read more at https://github.com/webpack/minimizer-webpack-plugin#number
    Details:
     * options.minify should be one of these:
-      function | non-empty string | object { path, export? }
+      function | non-empty string | object { path: non-empty string, export?: non-empty string }
       -> The minimizer itself: a function, a module path string (worker \`require\`s it), or \`{ path, export }\` for a named export.
       Details:
        * options.minify should be an instance of function.
        * options.minify should be a non-empty string.
        * options.minify should be an object:
-         object { path, export? }
+         object { path: non-empty string, export?: non-empty string }
     * options.minify should be an array:
-      [function | non-empty string | object { path, export? } | object { implementation, options?, filter? }, ...]
+      [function | non-empty string | object { path: non-empty string, export?: non-empty string } | object { implementation, options?, filter?: function }, ...]
     * options.minify should be an object:
-      object { implementation, options?, filter? }"
+      object { implementation, options?, filter?: function }"
 `;

test/embedded-source.test.js

@@ -26,6 +26,18 @@ const htmlMinify = require(WEBPACK_HTML_MINIFY);
 
 const fixture = (name) => path.resolve(__dirname, "./fixtures/embedded", name);
 
+/**
+ * A one-rule stylesheet with its declarations sorted: webpack 5.112's CSS
+ * minimizer emits them in a different order than 5.110 and 5.111 did.
+ * @param {string} css minified stylesheet
+ * @returns {string} the stylesheet with sorted declarations
+ */
+const sortDeclarations = (css) => {
+  const [, selector, body] = /^([^{]+)\{(.*)\}$/.exec(css);
+
+  return `${selector}{${body.split(";").sort().join(";")}}`;
+};
+
 /**
  * The three minify functions webpack's own `optimization.minimize` wires into
  * one plugin instance, which is what makes this work out of the box.
@@ -642,8 +654,10 @@ describe("embedded source", () => {
       const stats = await compile(compiler);
 
       expect(getErrors(stats)).toEqual([]);
-      expect(readAsset("sheet.css", compiler, stats)).toBe(
-        ".a{background:url(\"data:image/svg+xml,<svg xmlns='http://www.w3.org/2000/svg'> <rect /> </svg>\");color:red}",
+      expect(sortDeclarations(readAsset("sheet.css", compiler, stats))).toBe(
+        sortDeclarations(
+          ".a{background:url(\"data:image/svg+xml,<svg xmlns='http://www.w3.org/2000/svg'> <rect /> </svg>\");color:red}",
+        ),
       );
     });
 
@@ -739,8 +753,10 @@ describe("embedded source", () => {
       const stats = await compile(compiler);
 
       expect(getErrors(stats)).toEqual([]);
-      expect(readAsset("sheet.css", compiler, stats)).toBe(
-        ".a{background:url(\"data:image/svg+xml,<svg xmlns='http://www.w3.org/2000/svg'>   <rect  />   </svg>\");color:red}",
+      expect(sortDeclarations(readAsset("sheet.css", compiler, stats))).toBe(
+        sortDeclarations(
+          ".a{background:url(\"data:image/svg+xml,<svg xmlns='http://www.w3.org/2000/svg'>   <rect  />   </svg>\");color:red}",
+        ),
       );
     });
   });

test/validate-options.test.js

@@ -1,13 +1,37 @@
+import { validate } from "schema-utils";
+
 import MinimizerPlugin from "../src";
+import check from "../src/options.check";
+import schema from "../src/options.json";
 
 import { getCompiler } from "./helpers";
 
+/**
+ * Whether the full validation accepts the options.
+ * @param {EXPECTED_ANY} options plugin options
+ * @returns {boolean} true when valid
+ */
+const isValid = (options) => {
+  try {
+    validate(/** @type {EXPECTED_ANY} */ (schema), options);
+  } catch (_err) {
+    return false;
+  }
+
+  return true;
+};
+
 /**
  * @param {EXPECTED_ANY} options plugin options
  * @returns {import("webpack").Compiler} compiler
  */
-const createCompiler = (options) =>
-  getCompiler({ plugins: [new MinimizerPlugin(options)] });
+const createCompiler = (options) => {
+  // The precompiled check has to agree with the schema it was compiled from,
+  // a valid value is never validated against the schema itself
+  expect(check(options === undefined ? {} : options)).toBe(isValid(options));
+
+  return getCompiler({ plugins: [new MinimizerPlugin(options)] });
+};
 
 describe("validation", () => {
   it("validate", () => {

types/options.check.d.ts

@@ -0,0 +1,16 @@
+export = validate11;
+declare function validate11(
+  data: any,
+  {
+    instancePath,
+    parentData,
+    parentDataProperty,
+    rootData,
+  }?: {
+    instancePath?: string | undefined;
+    rootData?: any;
+  },
+): boolean;
+declare namespace validate11 {
+  export { validate11 as default };
+}