refactor: remove webpack 4 file watcher api

Author: jantimon

lib/cached-child-compiler.js

@@ -26,7 +26,7 @@
 /** @typedef {import("webpack/lib/Compiler.js")} WebpackCompiler */
 /** @typedef {import("webpack/lib/Compilation.js")} WebpackCompilation */
 /** @typedef {{hash: string, entry: any, content: string }} ChildCompilationResultEntry */
-/** @typedef {import("./webpack4/file-watcher-api").Snapshot} Snapshot */
+/** @typedef {import("./file-watcher-api").Snapshot} Snapshot */
 /** @typedef {{fileDependencies: string[], contextDependencies: string[], missingDependencies: string[]}} FileDependencies */
 /** @typedef {{
   dependencies: FileDependencies,

lib/file-watcher-api.js

@@ -1,14 +1,71 @@
 // @ts-check
+/** @typedef {import("webpack/lib/Compilation.js")} WebpackCompilation */
+/** @typedef {import("webpack/lib/FileSystemInfo").Snapshot} Snapshot */
+'use strict';
+
+/**
+ *
+ * @param {{fileDependencies: string[], contextDependencies: string[], missingDependencies: string[]}} fileDependencies
+ * @param {WebpackCompilation} mainCompilation
+ * @param {number} startTime
+ */
+function createSnapshot (fileDependencies, mainCompilation, startTime) {
+  return new Promise((resolve, reject) => {
+    mainCompilation.fileSystemInfo.createSnapshot(
+      startTime,
+      fileDependencies.fileDependencies,
+      fileDependencies.contextDependencies,
+      fileDependencies.missingDependencies,
+      null,
+      (err, snapshot) => {
+        if (err) {
+          return reject(err);
+        }
+        resolve(snapshot);
+      }
+    );
+  });
+}
+
 /**
- * To use the available webpack core api
- * we have to use different child compilers
- * depending on the used webpack version
+ * Returns true if the files inside this snapshot
+ * have not been changed
+ *
+ * @param {Snapshot} snapshot
+ * @param {WebpackCompilation} mainCompilation
+ * @returns {Promise<boolean>}
  */
-const webpackMajorVersion = Number(require('webpack/package.json').version.split('.')[0]);
-
-// Typescript hack to test only the webpack 4 code
-/** @type {import('./webpack4/file-watcher-api')} */
-module.exports = webpackMajorVersion === 4
-  ? require('./webpack4/file-watcher-api.js')
-  // Hack to ignore './webpack5/file-watcher-api.js' from typescript:
-  : require('./webpack' + 5 + '/file-watcher-api.js');
+function isSnapShotValid (snapshot, mainCompilation) {
+  return new Promise((resolve, reject) => {
+    mainCompilation.fileSystemInfo.checkSnapshotValid(
+      snapshot,
+      (err, isValid) => {
+        if (err) {
+          reject(err);
+        }
+        resolve(isValid);
+      }
+    );
+  });
+}
+
+/**
+ * Ensure that the files keep watched for changes
+ * and will trigger a recompile
+ *
+ * @param {WebpackCompilation} mainCompilation
+ * @param {{fileDependencies: string[], contextDependencies: string[], missingDependencies: string[]}} fileDependencies
+ */
+function watchFiles (mainCompilation, fileDependencies) {
+  Object.keys(fileDependencies).forEach((depencyTypes) => {
+    fileDependencies[depencyTypes].forEach(fileDependency => {
+      mainCompilation[depencyTypes].add(fileDependency);
+    });
+  });
+}
+
+module.exports = {
+  createSnapshot,
+  isSnapShotValid,
+  watchFiles
+};