0.4.2 • Public • Published

grunt-yaml Build Status

Compiles YAML to JSON.

Getting Started

If you haven't used grunt before, be sure to check out the Getting Started guide.

From the same directory as your project's Gruntfile and package.json, install this plugin with the following command:

npm install grunt-yaml --save-dev

Once that's done, add this line to your project's Gruntfile:


If the plugin has been installed correctly, running grunt --help at the command line should list the newly-installed plugin's task or tasks. In addition, the plugin should be listed in package.json as a devDependency, which ensures that it will be installed whenever the npm install command is run.

The "yaml" task


In your project's Gruntfile, add a section named yaml to the data object passed into grunt.initConfig().

  yaml: {
    your_target: {
      options: {
        ignored: /^_/,
        space: 4,
        customTypes: {
          '!include scalar': function(value, yamlLoader) {
            return yamlLoader(value);
          '!max sequence': function(values) {
            return Math.max.apply(null, values);
          '!extend mapping': function(value, yamlLoader) {
            return _.extend(yamlLoader(value.basePath), value.partial);
      files: [
        {expand: true, cwd: 'yaml_directory/', src: ['**/*.yml'], dest: 'output_directory/'}

In a situation where you do not want to output a file, but want to manipulate the data on your own, you can provide a middleware function and disable the destination write process:

  yaml: {
    your_target: {
      options: {
        disableDest: true,    // Grunt will not create a config.json as per the destination of the files object
        middleware: function(response, json, src, dest){
          console.log(response);    // YAML data
          console.log(json);        // Stringified JSON
          console.log(src);         // Source file path
          console.log(dest);        // Destination file path
        space: 4
      files: {
        'config.json': ['config.yml']



Type: RegExp or String Default value: null

A value that specifies file pattern not to compile.

Type: Number Default value: 2

A value that is given to JSON.stringify for pretty-printing.


Type: Object Default value: {}

A Object that defines custom types to js-yaml. A Object key is a tag and loadKind pair which is separated with a white space (e.g. !include scalar or !max sequence, !extend mapping). A Object value is a wrapper of loadResolver function which take value and yamlLoader arguments.

See also js-yaml document.


Type: Function Default value: function(response, json, src, dest) {}

A function which provides you an interface to manipulate the YAML before it becomes JSON, or manipulate the JSON after being stringified.


Type: Boolean Default value: false

A boolean flag which will prevent grunt-yaml from creating an output file if you would like to just work with the middleware function.


Type: Boolean Default value: false

A boolean flag which makes js-yaml to throw errors instead of warnings.


Type: String Default value: grunt.file.defaultEncoding

An override to the default buffer encoding used to read in the YAML file (


Type: String Default value: grunt.file.defaultEncoding

An override to the default buffer encoding used to write out the JSON file (grunt.file.write).

Usage Examples

See my repository.


In lieu of a formal styleguide, take care to maintain the existing coding style. Add unit tests for any new or changed functionality. Lint and test your code using grunt.

Release History

  • 2014-07-12   v0.4.1   Add writeEncoding and readEncoding options.
  • 2014-01-23   v0.4.0   Change yamlLoader behavior for showing the file name on js-yaml error, and add strict option.
  • 2014-01-18   v0.3.1   Use grunt.warn on js-yaml error.
  • 2014-01-17   v0.3.0   Introduce customTypes option for js-yaml v0.3.X. (Remove constructors option)
  • 2014-01-17   v0.2.2   Add src and dest path to middleware.
  • 2013-06-26   v0.2.1   Add middleware and disableDest options.
  • 2013-05-10   v0.2.0   Use files format.
  • 2013-04-14   v0.1.2   Support for grunt 0.4.0.
  • 2013-02-09   v0.1.1   Support for grunt 0.4.0rc7.
  • 2012-12-22   v0.1.0   First release.


Copyright (c) 2012 Shogo Iwano Licensed under the MIT license.



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