[resolvers/webpack] [new] add cache option

Author: seiyab

resolvers/webpack/CHANGELOG.md

@@ -4,6 +4,7 @@ This project adheres to [Semantic Versioning](https://semver.org/).
 This change log adheres to standards from [Keep a CHANGELOG](https://keepachangelog.com).
 
 ## Unreleased
+- [new] add cache option ([#3100], thanks [@seiyab])
 
 ## 0.13.9 - 2024-09-02
 - [refactor] simplify loop ([#3029], thanks [@fregante])
@@ -182,6 +183,7 @@ This change log adheres to standards from [Keep a CHANGELOG](https://keepachange
 ### Added
  - `interpret` configs (such as `.babel.js`). Thanks to [@gausie] for the initial PR ([#164], ages ago! 😅) and [@jquense] for tests ([#278]).
 
+[#3100]: https://github.com/import-js/eslint-plugin-import/pull/3100
 [#3029]: https://github.com/import-js/eslint-plugin-import/pull/3029
 [#2287]: https://github.com/import-js/eslint-plugin-import/pull/2287
 [#2023]: https://github.com/import-js/eslint-plugin-import/pull/2023
@@ -247,6 +249,7 @@ This change log adheres to standards from [Keep a CHANGELOG](https://keepachange
 [@Rogeres]: https://github.com/Rogeres
 [@Satyam]: https://github.com/Satyam
 [@Schweinepriester]: https://github.com/Schweinepriester
+[@seiyab]: https://github.com/seiyab
 [@SkeLLLa]: https://github.com/SkeLLLa
 [@taion]: https://github.com/taion
 [@toshafed]: https://github.com/toshafed

resolvers/webpack/README.md

@@ -94,6 +94,17 @@ settings:
         production: true
 ```
 
+If your config is set as a function, it will be evaluated at every resolution. You have an option to prevent this by caching it using the `cache` parameter:
+
+```yaml
+---
+settings:
+  import/resolver:
+    webpack:
+      config: 'webpack.config.js'
+      cache: true
+```
+
 ## Support
 
 [Get supported eslint-import-resolver-webpack with the Tidelift Subscription](https://tidelift.com/subscription/pkg/npm-eslint-import-resolver-webpack?utm_source=npm-eslint-import-resolver-webpack&utm_medium=referral&utm_campaign=readme)

resolvers/webpack/index.js

@@ -311,6 +311,22 @@ function getResolveSync(configPath, webpackConfig, cwd) {
   return cached.value;
 }
 
+const _evalCache = new Map();
+function evaluateFunctionConfigCached(configPath, webpackConfig, env, argv) {
+  const cacheKey = JSON.stringify({ configPath, args: [env, argv] });
+  if (_evalCache.has(cacheKey)) {
+    return _evalCache.get(cacheKey);
+  }
+  const cached = webpackConfig(env, argv);
+  _evalCache.set(cacheKey, cached);
+
+  while (_evalCache.size > MAX_CACHE) {
+    // remove oldest item
+    _evalCache.delete(_evalCache.keys().next().value);
+  }
+  return cached;
+}
+
 /**
  * Find the full path to 'source', given 'file' as a full reference path.
  *
@@ -354,6 +370,7 @@ exports.resolve = function (source, file, settings) {
   const configIndex = settings && settings['config-index'];
   const env = settings && settings.env;
   const argv = settings && typeof settings.argv !== 'undefined' ? settings.argv : {};
+  const shouldCacheFunctionConfig = settings && settings.cache;
   let packageDir;
 
   let configPath = typeof _configPath === 'string' && _configPath.startsWith('.')
@@ -398,7 +415,9 @@ exports.resolve = function (source, file, settings) {
   }
 
   if (typeof webpackConfig === 'function') {
-    webpackConfig = webpackConfig(env, argv);
+    webpackConfig = shouldCacheFunctionConfig
+      ? evaluateFunctionConfigCached(configPath, webpackConfig, env, argv)
+      : webpackConfig(env, argv);
   }
 
   if (isArray(webpackConfig)) {

resolvers/webpack/test/cache.js

@@ -0,0 +1,48 @@
+'use strict';
+
+const chai =  require('chai');
+const expect = chai.expect;
+const path = require('path');
+
+const resolve = require('../index').resolve;
+
+const file = path.join(__dirname, 'files', 'src', 'jsx', 'dummy.js');
+
+describe('cache', function () {
+  it('can distinguish different config files', function () {
+    const setting1 = {
+      config: require(path.join(__dirname, './files/webpack.function.config.js')),
+      argv: {
+        mode: 'test',
+      },
+      cache: true,
+    };
+    expect(resolve('baz', file, setting1)).to.have.property('path')
+      .and.equal(path.join(__dirname, 'files', 'some', 'bar', 'bar.js'));
+    const setting2 = {
+      config: require(path.join(__dirname, './files/webpack.function.config.multiple.js')),
+      cache: true,
+    };
+    expect(resolve('baz', file, setting2)).to.have.property('path')
+      .and.equal(path.join(__dirname, 'files', 'some', 'goofy', 'path', 'foo.js'));
+  });
+
+  it('can distinguish different config', function () {
+    const setting1 = {
+      config: require(path.join(__dirname, './files/webpack.function.config.js')),
+      env: {
+        dummy: true,
+      },
+      cache: true,
+    };
+    expect(resolve('bar', file, setting1)).to.have.property('path')
+      .and.equal(path.join(__dirname, 'files', 'some', 'goofy', 'path', 'bar.js'));
+    const setting2 = {
+      config: require(path.join(__dirname, './files/webpack.function.config.multiple.js')),
+      cache: true,
+    };
+    const result = resolve('bar', file, setting2);
+    expect(result).not.to.have.property('path');
+    expect(result).to.have.property('found').to.be.false;
+  });
+});

resolvers/webpack/test/files/webpack.function.config.multiple.js

@@ -7,6 +7,7 @@ module.exports = [function(env) {
       alias: {
         'foo': path.join(__dirname, 'some', 'goofy', 'path', 'foo.js'),
         'bar': env ? path.join(__dirname, 'some', 'goofy', 'path', 'bar.js') : undefined,
+        'baz': path.join(__dirname, 'some', 'goofy', 'path', 'foo.js'),
         'some-alias': path.join(__dirname, 'some'),
       },
       modules: [