Can Yeoman generators update existing files?

Question

So just to give you some context, I'm trying to create a generator that will create some files (based on user input of course) as well as update some existing files in the project (like adding a new route for example).

Creating the files using this.template is no problem... the question is: is there any way to do this with Yeoman without having to read the file using Node and doing some fanciful find and replace?

Answer 1

Ok, so I found the answer to my question.

Addy Osmani showed me where to look in this thread on twitter, and then I later found this link which shows exactly what I need.

The gist of it boils down to two functions : readFileAsString and write. Usage is as follows:

var path = "/path/to/file.html",     file = this.readFileAsString(path);  /* make modifications to the file string here */  this.write(path, file); 

Edit: I've also blogged about this on my blog.

 EDIT 1

As mentionned in comments by Toilal :

The write method doesn't exists anymore, and must be replaced by writeFileFromString (arguments are also reversed) – Toilal

EDIT 2

And then, as mentionned in comments by ivoba:

this.writeFileFromString & this.readFileAsString are deprecated, github.com/yeoman/html-wiring should be used by now, things change :) – ivoba

Answer 2

Yeoman also provides a more elegant way of fs operations using mem-fs-editor.

You can use this.fs.copy, passing a process function as an option to do any modifications to the content:

this.fs.copy(path, newPath, {     process: function(content) {          /* Any modification goes here. Note that contents is a Buffer object */          var regEx = new RegExp('old string', 'g');         var newContent = content.toString().replace(regEx, 'new string');         return newContent;     } }); 

This way you can also take advantage of mem-fs-editor features.