From 55c1a46361709e99239f7ed0dfc4d88da0ce3b1b Mon Sep 17 00:00:00 2001
From: Daniel Woznicki <danwoz@docspot.com>
Date: Thu, 31 May 2018 16:27:16 -0700
Subject: [PATCH] Add options.onlyBuildOnce to only build html files on initial
 compilation Add test for onlyBuildOnce option

---
 index.js            | 10 +++++++++-
 spec/CachingSpec.js | 30 ++++++++++++++++++++++++++++++
 2 files changed, 39 insertions(+), 1 deletion(-)

diff --git a/index.js b/index.js
index 5d6d28d0..0c558afd 100644
--- a/index.js
+++ b/index.js
@@ -33,8 +33,10 @@ class HtmlWebpackPlugin {
       chunksSortMode: 'auto',
       meta: {},
       title: 'Webpack App',
-      xhtml: false
+      xhtml: false,
+      onlyBuildOnce: false
     }, options);
+    this.isBuilt = false;
   }
 
   apply (compiler) {
@@ -67,6 +69,10 @@ class HtmlWebpackPlugin {
 
     // Backwards compatible version of: compiler.hooks.make.tapAsync()
     (compiler.hooks ? compiler.hooks.make.tapAsync.bind(compiler.hooks.make, 'HtmlWebpackPlugin') : compiler.plugin.bind(compiler, 'make'))((compilation, callback) => {
+      if (self.options.onlyBuildOnce && self.isBuilt) {
+        callback();
+        return;
+      }
       // Compile the template (queued)
       compilationPromise = childCompiler.compileTemplate(self.options.template, compiler.context, self.options.filename, compilation)
         .catch(err => {
@@ -88,6 +94,7 @@ class HtmlWebpackPlugin {
 
     // Backwards compatible version of: compiler.plugin.emit.tapAsync()
     (compiler.hooks ? compiler.hooks.emit.tapAsync.bind(compiler.hooks.emit, 'HtmlWebpackPlugin') : compiler.plugin.bind(compiler, 'emit'))((compilation, callback) => {
+      if (self.options.onlyBuildOnce && self.isBuilt) return callback();
       const applyPluginsAsyncWaterfall = self.applyPluginsAsyncWaterfall(compilation);
       // Get chunks info as json
       // Note: we're excluding stuff that we don't need to improve toJson serialization speed.
@@ -223,6 +230,7 @@ class HtmlWebpackPlugin {
         }).then(() => null))
         // Let webpack continue with it
         .then(() => {
+          if (self.options.onlyBuildOnce) self.isBuilt = true;
           callback();
         });
     });
diff --git a/spec/CachingSpec.js b/spec/CachingSpec.js
index 4377f94f..3cdddbad 100644
--- a/spec/CachingSpec.js
+++ b/spec/CachingSpec.js
@@ -157,4 +157,34 @@ describe('HtmlWebpackPluginCaching', function () {
       })
       .then(done);
   });
+  it('should not compile the webpack html if any file is changed if only allowed to build on first compile', function (done) {
+    var template = path.join(__dirname, 'fixtures/plain.html');
+    var entry = path.join(__dirname, 'fixtures/index.js');
+    var htmlWebpackPlugin = new HtmlWebpackPlugin({
+      template: template,
+      onlyBuildOnce: true
+    });
+    var childCompilerHash;
+    var compiler = setUpCompiler(htmlWebpackPlugin);
+    compiler.run()
+      // Change the template and entry files and compile again
+      .then(function () {
+        childCompilerHash = htmlWebpackPlugin.childCompilerHash;
+        compiler.simulateFileChange(template, {footer: '<!-- 1 -->'});
+        compiler.simulateFileChange(entry, {footer: '//1'});
+        return compiler.run();
+      })
+      .then(function (stats) {
+        // Verify that only one file was built
+        expect(getCompiledModuleCount(stats.toJson()))
+          .toBe(1);
+        // Verify that the html was processed only during the initial build
+        expect(htmlWebpackPlugin.evaluateCompilationResult.calls.count())
+          .toBe(1);
+        // Verify that the child compilation was executed only once
+        expect(htmlWebpackPlugin.childCompilerHash)
+          .toBe(childCompilerHash);
+      })
+      .then(done);
+  });
 });