Use Grunt and Tiny Validator tv4 to validate files against json-schema draft v4
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Use grunt and Tiny Validator tv4 to validate values against json-schema draft v4

Getting Started

This plugin requires Grunt >=0.4.1

If you haven't used Grunt before, be sure to check out the Getting Started guide, as it explains how to create a Gruntfile as well as install and use Grunt plugins. Once you're familiar with that process, you may install this plugin with this command:

$ npm install grunt-tv4 --save-dev

Once the plugin has been installed, it may be enabled inside your Gruntfile with this line of JavaScript:


The "tv4" task


API change

As of version v0.2.0 the API was changed to follow the Grunt options- and file-selection conventions. The old pattern (which abused the destination-specifier) is no longer supported. The readme for the previous API can be found here.

The root schema must now to be specified as options.root.


Basic usage

Validate from .json files:

    tv4: {
        options: {
            root: grunt.file.readJSON('schema/main.json')
        myTarget: {
            src: ['data/*.json']

Valdiate values:

    tv4: {
        myTarget: {
            options: {
                root: {
                    type: 'object',
                    properties: { ... }
            values: [
                { ... },
                { ... }

Advanced usage

    tv4: {
        options: {
            // specify the main schema, one of:
            // - path to json
            // - http-url
            // - schema object
            // - callback that returns one of the above
            root: grunt.file.readJSON('schema/main.json'),

            // show multiple errors per file (off by default)
            multi: true,

            // create a new tv4 instance for every target (off by default)
            fresh: true,

            // add schemas in bulk (each required to have an 'id' property) (can be a callback)
            add: [

            // set schemas by URI (can be a callback)
            schemas: {
                '': grunt.file.readJSON('schema/apple.json'),
                '': grunt.file.readJSON('schema/pear.json')

            // map of custom formats passed to tv4.addFormat()
            formats: {
                date: function (data, schema) {
                    if (typeof data !== 'string' || !dateRegex.test(data)) {
                        return 'value must be string of the form: YYYY-MM-DD';
                    return null;

            // passed to tv4.validate()
            checkRecursive: false,
            // passed to tv4.validate()
            banUnknownProperties: false,
            // passed tv4.language()
            language: 'de',
            // passed tv4.addLanguage()
            languages: {
                'de': { ... }
        // load json from disk
        myFiles: {
            src: ['data/*.json', 'data/fruit/**/*.json']

        myValues: {
            // validate values
            values: [

        myValueMap: {
            // alternately pass as object and the keys will be used as labels in the reports
            values: {
                'apple': grunt.file.readJSON('data/apple.json'),
                'pear': grunt.file.readJSON('data/pear.json')

        myCallback: {
            // alternately pass a function() to return a collection of values (array or object)
            values: function() {
                return {
                    'apple': grunt.file.readJSON('data/apple.json'),
                    'pear': grunt.file.readJSON('data/pear.json')


  • 0.5.0
    • Bring travis node targets up to date
    • Remove grunt-cli as a devDependency (it should be installed globally)
    • devDependencies: grunt 1.0.1
    • peerDependencies: grunt >= 0.4.1
  • 0.4.2
    • Typos fixed in code examples.
    • Update grunt in peerDependencies to support grunt v1.
    • Update docs to reflect change of project ownership.
  • 0.4.0 - Updated some dependencies. root, add and schemas can be a callback function (for lazy init).
  • 0.3.0 - Big internal rewrite:
    • Added .values option.
    • Extracted reporting to tv4-reporter, miniwrite and ministyle.
    • Moved loader logic to own stand-alone module (for later extraction)
    • Extracted test-running logic to own module (for later extraction)
  • 0.2.1 - Added support to report subErrors (for anyOf/oneOf)
  • 0.2.0 - Updated to follow the Grunt conventions.
  • 0.1.4 - Updated tv4 to version 1.0.11
    • Added support for tv4.addFormat() / languages / checkRecursive / banUnknownProperties.
  • 0.1.3 - Support for loading remote references (JSON Schemas $ref).
  • 0.1.1 - Bugfixes and improved reporting
  • 0.1.0 - First release with synchronous validation


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.

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