[Grunt] Watch && grunt-contrib-watch

Watch is an essential component of any Grunt build, and you will find yourself using it in almost every project.

How to install?

1. Install grunt first if you don't have yet. Check the first article for Grunt.

2. Install grunt-contrib-watch

npm install grunt-contrib-watch

What is watch used for?

A simple example is that, it can watch a file if the file changed then trigger the task to run.

How to use?

You have a log.txt file, and you want to watch this file.

1. load npm task:

grunt.loadNpmTasks('grunt-contrib-watch');

2. set up watch:

    grunt.initConfig({
        watch: {
            files: ['log.txt'],
            tasks: ['pat']
        }
    });

3. add task:

    grunt.registerTask('pat', function(){
        grunt.log.writeln('I am watching you!');
    });

4. Start watch:

#In cmd

$ grunt watch

File the file is modified: