feat: added the hashStrategy option

Author: subzey

README.md

@@ -872,6 +872,36 @@ module.exports = {
 };
 ```
 
+##### `hashStrategy`
+
+Type: `'resource-path-and-local-name' | 'minimal-subset'`
+Default: `'resource-path-and-local-name'`
+
+Should local name be used when computing the hash.
+
+- `'resource-path-and-local-name'` Both resource path and local name are used when hashing. Each identifier in a module gets its own hash digest, always.
+- `'minimal-subset'` Auto detect if identifier names can be omitted from hashing. Use this value to optimize the output for better GZIP or Brotli compression.
+
+**webpack.config.js**
+
+```js
+module.exports = {
+  module: {
+    rules: [
+      {
+        test: /\.css$/i,
+        loader: "css-loader",
+        options: {
+          modules: {
+            hashStrategy: "minimal-subset",
+          },
+        },
+      },
+    ],
+  },
+};
+```
+
 ##### `localIdentRegExp`
 
 Type: `String|RegExp`

src/options.json

@@ -114,6 +114,11 @@
               "link": "https://github.com/webpack-contrib/css-loader#localidenthashdigestlength",
               "type": "number"
             },
+            "hashStrategy": {
+              "description": "Allows to specify should localName be used when computing the hash.",
+              "link": "https://github.com/webpack-contrib/css-loader#hashstrategy",
+              "enum": ["resource-path-and-local-name", "minimal-subset"]
+            },
             "localIdentRegExp": {
               "description": "Allows to specify custom RegExp for local ident name.",
               "link": "https://github.com/webpack-contrib/css-loader#localidentregexp",

src/utils.js

@@ -330,14 +330,17 @@ function defaultGetLocalIdent(
   localName,
   options
 ) {
-  const { context, hashSalt } = options;
+  const { context, hashSalt, hashStrategy } = options;
   const { resourcePath } = loaderContext;
   const relativeResourcePath = normalizePath(
     path.relative(context, resourcePath)
   );
 
   // eslint-disable-next-line no-param-reassign
-  options.content = `${relativeResourcePath}\x00${localName}`;
+  options.content =
+    hashStrategy === "minimal-subset" && /\[local\]/.test(localIdentName)
+      ? relativeResourcePath
+      : `${relativeResourcePath}\x00${localName}`;
 
   let { hashFunction, hashDigest, hashDigestLength } = options;
   const matches = localIdentName.match(
@@ -756,6 +759,7 @@ function getModulesPlugins(options, loaderContext) {
     localIdentHashDigest,
     localIdentHashDigestLength,
     localIdentRegExp,
+    hashStrategy,
   } = options.modules;
 
   let plugins = [];
@@ -780,6 +784,7 @@ function getModulesPlugins(options, loaderContext) {
                 hashFunction: localIdentHashFunction,
                 hashDigest: localIdentHashDigest,
                 hashDigestLength: localIdentHashDigestLength,
+                hashStrategy,
                 regExp: localIdentRegExp,
               }
             );
@@ -798,6 +803,7 @@ function getModulesPlugins(options, loaderContext) {
                 hashFunction: localIdentHashFunction,
                 hashDigest: localIdentHashDigest,
                 hashDigestLength: localIdentHashDigestLength,
+                hashStrategy,
                 regExp: localIdentRegExp,
               }
             );