fix: support webpack 5 (#199)

package.json

@@ -35,7 +35,7 @@
   ],
   "peerDependencies": {
     "stylelint": "^9.0.0 || ^10.0.0 || ^11.0.0 || ^12.0.0",
-    "webpack": "^4.0.0"
+    "webpack": "^4.0.0 || ^5.0.0"
   },
   "dependencies": {
     "arrify": "^2.0.1",

src/LintDirtyModulesPlugin.js

@@ -12,18 +12,20 @@ export default class LintDirtyModulesPlugin {
   }
 
   apply(compilation, callback) {
+    const fileTimestamps = compilation.fileTimestamps || new Map();
+
     if (this.isFirstRun) {
       this.isFirstRun = false;
-      this.prevTimestamps = compilation.fileTimestamps;
+      this.prevTimestamps = fileTimestamps;
       callback();
       return;
     }
 
     const dirtyOptions = { ...this.options };
     const glob = dirtyOptions.files.join('|').replace(/\\/g, '/');
-    const changedFiles = this.getChangedFiles(compilation.fileTimestamps, glob);
+    const changedFiles = this.getChangedFiles(fileTimestamps, glob);
 
-    this.prevTimestamps = compilation.fileTimestamps;
+    this.prevTimestamps = fileTimestamps;
 
     if (changedFiles.length) {
       dirtyOptions.files = changedFiles;
@@ -34,8 +36,15 @@ export default class LintDirtyModulesPlugin {
   }
 
   getChangedFiles(fileTimestamps, glob) {
-    const hasFileChanged = (filename, timestamp) => {
-      const prevTimestamp = this.prevTimestamps.get(filename);
+    const getTimestamps = (fileSystemInfoEntry) => {
+      return fileSystemInfoEntry && fileSystemInfoEntry.timestamp
+        ? fileSystemInfoEntry.timestamp
+        : fileSystemInfoEntry;
+    };
+
+    const hasFileChanged = (filename, fileSystemInfoEntry) => {
+      const prevTimestamp = getTimestamps(this.prevTimestamps.get(filename));
+      const timestamp = getTimestamps(fileSystemInfoEntry);
 
       return (prevTimestamp || this.startTime) < (timestamp || Infinity);
     };

test/LintDirtyModulesPlugin.test.js

@@ -47,7 +47,7 @@ describe('lint dirty modules only', () => {
   });
 
   it('not linter if files are not changed', () => {
-    const fileTimestamps = new Map([['not-changed.scss', 1]]);
+    const fileTimestamps = new Map([['not-changed.scss', { timestamp: 1 }]]);
 
     plugin.isFirstRun = false;
     plugin.prevTimestamps = fileTimestamps;