[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?

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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?

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

 

How to use?

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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: