add support for webpack4

Author: andriijas

lib/plugin.js

@@ -33,16 +33,14 @@ ManifestPlugin.prototype.apply = function(compiler) {
   var seed = this.opts.seed || {};
   var moduleAssets = {};
 
-  compiler.plugin("compilation", function (compilation) {
-    compilation.plugin('module-asset', function (module, file) {
-      moduleAssets[file] = path.join(
-          path.dirname(file),
-          path.basename(module.userRequest)
-      );
-    });
-  });
-
-  compiler.plugin('emit', function(compilation, compileCallback) {
+  var moduleAsset = function (module, file) {
+    moduleAssets[file] = path.join(
+      path.dirname(file),
+      path.basename(module.userRequest)
+    );
+  };
+
+  var emit = function(compilation, compileCallback) {
     var publicPath = compilation.options.output.publicPath;
     var stats = compilation.getStats().toJson();
 
@@ -61,7 +59,7 @@ ManifestPlugin.prototype.apply = function(compiler) {
           path: path,
           chunk: chunk,
           name: name,
-          isInitial: chunk.isInitial ? chunk.isInitial() : chunk.initial,
+          isInitial: chunk.isInitial ? chunk.isInitial() : chunk.isOnlyInitial(),
           isChunk: true,
           isAsset: false,
           isModuleAsset: false
@@ -172,14 +170,32 @@ ManifestPlugin.prototype.apply = function(compiler) {
 
     // NOTE: make sure webpack is not writing multiple manifests simultaneously
     lock(function(release) {
-      compiler.plugin('after-emit', function(compilation, cb) {
-        release();
-        cb();
-      });
+      if (compiler.hooks) {
+        compiler.hooks.afterEmit.tap('ManifestPlugin', function(compilation) {
+          release();
+        });
+      } else {
+        compiler.plugin('after-emit', function(compilation, cb) {
+          release();
+          cb();
+        });
+  
+        compilation.applyPluginsAsync('webpack-manifest-plugin-after-emit', manifest, compileCallback);
+      }
+    });
+  }.bind(this);
 
-      compilation.applyPluginsAsync('webpack-manifest-plugin-after-emit', manifest, compileCallback);
+  if (compiler.hooks) {
+    compiler.hooks.compilation.tap('ManifestPlugin', function (compilation) {
+      compilation.hooks.moduleAsset.tap('ManifestPlugin', moduleAsset);
     });
-  }.bind(this));
+    compiler.hooks.emit.tap('ManifestPlugin', emit);
+  } else {
+    compiler.plugin('compilation', function (compilation) {
+      compilation.plugin('module-asset', moduleAsset);
+    });
+    compiler.plugin('emit', emit);
+  }
 };
 
-module.exports = ManifestPlugin;
+module.exports = ManifestPlugin;

package.json

@@ -12,7 +12,7 @@
     "node": ">=4"
   },
   "peerDependencies": {
-    "webpack": "2 || 3"
+    "webpack": "2 || 3 || 4"
   },
   "devDependencies": {
     "codecov": "^2.2.0",