From eb4a618d4fff559b90d4a9884502bedaf35e60a6 Mon Sep 17 00:00:00 2001
From: Tiberiu Zuld <tiberiuzuld@gmail.com>
Date: Sun, 9 Dec 2018 18:03:52 +0200
Subject: [PATCH] feat: throw error if nothing to inject

---
 README.md                 |  8 +++++++
 src/inject/index.js       |  3 +++
 src/inject/inject_test.js | 44 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 55 insertions(+)

diff --git a/README.md b/README.md
index 4f34776..61b38d7 100644
--- a/README.md
+++ b/README.md
@@ -876,6 +876,14 @@ Default: `false`
 Lower the verbosity by setting this to true, suppressing the logging of successful injections.
 
 
+#### options.throwErrorIfNoInject
+Type: `Boolean`
+
+Default: `false`
+
+If there is nothing to inject throw an error.
+
+
 #### ~~options.templateString~~
 
 ***DEPRECATED!***
diff --git a/src/inject/index.js b/src/inject/index.js
index 5900d1d..c33b46b 100644
--- a/src/inject/index.js
+++ b/src/inject/index.js
@@ -46,6 +46,7 @@ module.exports = exports = function (sources, opt) {
 
   // Defaults:
   opt.quiet = bool(opt, 'quiet', false);
+  opt.throwErrorIfNoInject = bool(opt, 'throwErrorIfNoInject', false);
   opt.relative = bool(opt, 'relative', false);
   opt.addRootSlash = bool(opt, 'addRootSlash', !opt.relative);
   opt.transform = defaults(opt, 'transform', transform);
@@ -109,6 +110,8 @@ function getNewContent(target, collection, opt) {
     if (filesCount) {
       var pluralState = filesCount > 1 ? 's' : '';
       log(cyan(filesCount) + ' file' + pluralState + ' into ' + magenta(target.relative) + '.');
+    } else if (opt.throwErrorIfNoInject === true) {
+      throw error('Nothing to inject into ' + magenta(target.relative) + '.');
     } else {
       log('Nothing to inject into ' + magenta(target.relative) + '.');
     }
diff --git a/src/inject/inject_test.js b/src/inject/inject_test.js
index c602a71..e3c6baf 100644
--- a/src/inject/inject_test.js
+++ b/src/inject/inject_test.js
@@ -701,6 +701,50 @@ describe('gulp-inject', function () {
 
     streamShouldContain(stream, ['emptyTags3.html'], done);
   });
+
+  it('should throw an error when there is nothing to inject', function (done) {
+    var logOutput = [];
+    fancyLog.info = function (a, b) {
+      logOutput.push(a + ' ' + b);
+    };
+
+    var target = src(['templateWithExistingData2.html'], {read: true});
+
+    var sources = src([]);
+
+    var stream = target.pipe(inject(sources, {throwErrorIfNoInject: true}));
+
+    // Dummy data reader to make the `end` event be triggered
+    stream.on('data', function () {
+    });
+
+    stream.on('error', function (error) {
+      error.should.not.be.undefined();
+      logOutput.should.have.length(0);
+      done();
+    });
+  });
+
+  it('should log when there is nothing to inject', function (done) {
+    var logOutput = [];
+    fancyLog.info = function (a, b) {
+      logOutput.push(a + ' ' + b);
+    };
+    var target = src(['templateWithExistingData2.html'], {read: true});
+
+    var sources = src([]);
+
+    var stream = target.pipe(inject(sources));
+
+    // Dummy data reader to make the `end` event be triggered
+    stream.on('data', function () {
+    });
+
+    stream.on('end', function () {
+      logOutput.should.have.length(1);
+      done();
+    });
+  });
 });
 
 function src(files, opt) {