fix: remove the hash calculation if hash exists (#159)

Co-authored-by: Ivan Vasilov <ivan@hfour.com>

__snapshots__/test.js.snap

@@ -100,6 +100,15 @@ Object {
 }
 `;
 
+exports[`should use the hash from HtmlWebpackPlugin if option is set 1`] = `
+Object {
+  "css": Array [],
+  "js": Array [
+    "my-file.js?testHash",
+  ],
+}
+`;
+
 exports[`should used passed in publicPath 1`] = `
 Object {
   "css": Array [],

src/index.js

@@ -143,9 +143,14 @@ export default class AddAssetHtmlPlugin {
 
     let suffix = '';
     if (hash) {
-      const md5 = crypto.createHash('md5');
-      md5.update(compilation.assets[addedFilename].source());
-      suffix = `?${md5.digest('hex').substr(0, 20)}`;
+      // if the hash is set by html-webpack-plugin use that hash, else generate a new one
+      if (compilation.hash) {
+        suffix = `?${compilation.hash}`;
+      } else {
+        const md5 = crypto.createHash('md5');
+        md5.update(compilation.assets[addedFilename].source());
+        suffix = `?${md5.digest('hex').substr(0, 20)}`;
+      }
     }
 
     const resolvedPublicPath =

test.js

@@ -138,6 +138,22 @@ test('should skip adding sourcemap and gzipped files to compilation if set to fa
   expect(addFileToAssetsStub).toHaveBeenCalledWith('my-file.js', compilation);
 });
 
+test('should use the hash from HtmlWebpackPlugin if option is set', async () => {
+  const compilation = {
+    hash: 'testHash',
+    options: { output: {} },
+    assets: {
+      'my-file.js': { source: () => 'some source code is cool to have;' },
+    },
+  };
+  const pluginData = Object.assign({ assets: { js: [], css: [] } }, pluginMock);
+  const plugin = new AddAssetHtmlPlugin({ filepath: 'my-file.js', hash: true });
+
+  await plugin.addAllAssetsToCompilation(compilation, pluginData);
+
+  expect(pluginData.assets).toMatchSnapshot();
+});
+
 test('should include hash of file content if option is set', async () => {
   const compilation = {
     options: { output: {} },