在grunt中不存在时创建文件/文件夹的任务

Question

I'm trying to automate my testing and was wanting to automatically create test files for any javascript that is created on src folder. Here's a break down on my folder structure.

js
--src
  --sum.js
  --subtract.js
  --calculator.js
  --innerFolder
    --multiply.js
    --divide.js
--specs

So from the above folder structure what I want to do is create all the folder structure and files on my specs like this only if the file on the destination folder doesn't already exist :-

js
--src
  --sum.js
  --subtract.js
  --calculator.js
  --innerFolder
    --multiply.js
    --divide.js
--specs
  --sumSpec.js
  --subtractSpec.js
  --calculator.js
  --innerFolder
    --multiplySpec.js
    --divideSpec.js

My approach to tackle this is by watching all the files/folders on src folder doing :-

watch:{
  src : {
    files: ['src/**/*.*'],
    tasks:  //create files and folders on specs folders here
}

I came across grunt.file plugin and also have considered grunt-shell and making my own script to achieve this.

But I was wondering if there was already an easier way to do this.

Answer 1

Try the copy task along with the filter property:

grunt.initConfig({
  copy: {
    js: {
      expand: true,
      cwd: 'js/src',
      src: '**/*.js',
      dest: 'js/specs',
      filter: function(filepath) {
        var path = require('path');
        var dest = path.join(
          grunt.config('copy.js.dest'),
          // Remove the parent 'js/src' from filepath
          filepath.split(path.sep).slice(2).join(path.sep)
        );
        return !(grunt.file.exists(dest));
      },
    },
  },
  watch: {
    js: {
      files: ['js/src/**/*.js'],
      tasks: ['copy:js'],
    },
  },
});

Then you can have it copy files that don't exist as you edit or run grunt copy:js .