Change from Bundle & Minifier to Gulp in Visual Studio

When ASP.NET Core 1.0 was released Microsoft switched gulp for Mads Kristensen‘s Bundler & Minifier. This post is going to cover taking a project that is using Bundler & Minifier and change it to use gulp instead. Don’t take this as problem with Bundler & Minifier I am just more familiar with gulp and didn’t mix in another new tool.

The extension

There is a Bundler & Minifier extension available that make the change to gulp super simple. You could do all this yourself, but the extension seems to be the fastest way to convert without having to worry about htting. Click the Tools > Extensions and Updates menu. Then in the Extensions and Update dialog on the left select Online. Next on the top right enter “bundler & minifier” in the search box. Then click the download button next to Bundler & Minifier and follow the prompt to install and then restart Visual Studio.


The conversion to gulp

Right click on your project’s bundleconfig.json (this is the file that is used to configure the default bundling and minification stuff) and select Bundler & Minifier > Convet To Gulp.


This will show a warning dialog saying that the process will take a few minutes due to npm restores, etc. When the process is done you will now have a gulpfile.js file. The gulpfile.js file that is created will require bundleconfig.js in order to expose your existing tasks.

Required edit to bundleconfig.js

Since the generated gulpfile.js is using the existing tasks in bundleconfig.js all the comments must be removed from bundleconfig.js before gulp will work properly. This is due to comments not being valid json and the parser that gulp uses sees the json as being invalid. The following line exists in the generated gulpfile.js, but it is easy to miss so I wanted to call it out.

bundleconfig = require("./bundleconfig.json"); // make sure bundleconfig.json doesn't contain any comments

Wrapping up

package.json is the other file that got created during this process. If you are doing this manually don’t forget this file. I had tried this conversion manually once before and I am pretty sure this file is the reason I was not successful.

As I stated above I went the route of the extension so I wouldn’t miss anything and it worked out well. Now knowing what needs to be changed I could do it manually, but the extension works so well I recommend using it.

Thanks to Jon Galloway as I first saw this process at one of his talk at Code on the Beach.

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