refactor: require lint of stylelint only one time and create utils with helper functions

src/LintDirtyModulesPlugin.js

@@ -1,9 +1,11 @@
 import { isMatch } from 'micromatch';
 
 import linter from './linter';
+import { replaceBackslashes } from './utils';
 
 export default class LintDirtyModulesPlugin {
-  constructor(compiler, options) {
+  constructor(lint, compiler, options) {
+    this.lint = lint;
     this.compiler = compiler;
     this.options = options;
     this.startTime = Date.now();
@@ -22,14 +24,14 @@ export default class LintDirtyModulesPlugin {
     }
 
     const dirtyOptions = { ...this.options };
-    const glob = dirtyOptions.files.join('|').replace(/\\/g, '/');
+    const glob = replaceBackslashes(dirtyOptions.files.join('|'));
     const changedFiles = this.getChangedFiles(fileTimestamps, glob);
 
     this.prevTimestamps = fileTimestamps;
 
     if (changedFiles.length) {
       dirtyOptions.files = changedFiles;
-      linter(dirtyOptions, this.compiler, callback);
+      linter(this.lint, dirtyOptions, this.compiler, callback);
     } else {
       callback();
     }
@@ -53,7 +55,7 @@ export default class LintDirtyModulesPlugin {
 
     for (const [filename, timestamp] of fileTimestamps.entries()) {
       if (hasFileChanged(filename, timestamp) && isMatch(filename, glob)) {
-        changedFiles.push(filename.replace(/\\/g, '/'));
+        changedFiles.push(replaceBackslashes(filename));
       }
     }
 

src/index.js

@@ -1,41 +1,41 @@
 import { isAbsolute, join } from 'path';
 
-import arrify from 'arrify';
-
 import getOptions from './getOptions';
 import LintDirtyModulesPlugin from './LintDirtyModulesPlugin';
 import linter from './linter';
+import { parseFiles } from './utils';
 
 class StylelintWebpackPlugin {
   constructor(options = {}) {
     this.options = getOptions(options);
   }
 
   apply(compiler) {
-    const context = this.getContext(compiler);
-    const options = { ...this.options };
+    const options = {
+      ...this.options,
+      files: parseFiles(this.options.files, this.getContext(compiler)),
+    };
 
-    options.files = arrify(options.files).map((file) =>
-      join(context, '/', file).replace(/\\/g, '/')
-    );
+    // eslint-disable-next-line
+    const { lint } = require(options.stylelintPath);
 
     const plugin = { name: this.constructor.name };
 
     if (options.lintDirtyModulesOnly) {
-      const lintDirty = new LintDirtyModulesPlugin(compiler, options);
+      const lintDirty = new LintDirtyModulesPlugin(lint, compiler, options);
 
       /* istanbul ignore next */
       compiler.hooks.watchRun.tapAsync(plugin, (compilation, callback) => {
         lintDirty.apply(compilation, callback);
       });
     } else {
       compiler.hooks.run.tapAsync(plugin, (compilation, callback) => {
-        linter(options, compilation, callback);
+        linter(lint, options, compilation, callback);
       });
 
       /* istanbul ignore next */
       compiler.hooks.watchRun.tapAsync(plugin, (compilation, callback) => {
-        linter(options, compilation, callback);
+        linter(lint, options, compilation, callback);
       });
     }
   }

src/linter.js

@@ -1,12 +1,9 @@
 import StylelintError from './StylelintError';
 
-export default function linter(options, compiler, callback) {
+export default function linter(lint, options, compiler, callback) {
   let errors = [];
   let warnings = [];
 
-  // eslint-disable-next-line
-  const { lint } = require(options.stylelintPath);
-
   lint(options)
     .then(({ results }) => {
       ({ errors, warnings } = parseResults(options, results));

src/utils.js

@@ -0,0 +1,13 @@
+import { join } from 'path';
+
+import arrify from 'arrify';
+
+export function parseFiles(files, context) {
+  return arrify(files).map((file) =>
+    replaceBackslashes(join(context, '/', file))
+  );
+}
+
+export function replaceBackslashes(str) {
+  return str.replace(/\\/g, '/');
+}

test/LintDirtyModulesPlugin.test.js

@@ -10,7 +10,9 @@ describe('lint dirty modules only', () => {
   beforeAll(() => {
     callback = jest.fn();
 
-    plugin = new LintDirtyModulesPlugin(null, { files: ['**\\*.s?(c|a)ss'] });
+    plugin = new LintDirtyModulesPlugin(null, null, {
+      files: ['**\\*.s?(c|a)ss'],
+    });
   });
 
   beforeEach(() => {