@prantlf/grunt-jsonlint

Validates JSON/JSON5 files from grunt using jsonlint.

This is a fork of the original package with the following enhancements:

• Supports JSON Schema drafts 04, 06 and 07.
• Optionally recognizes JavaScript-style comments and single quoted strings.
• Optionally ignores trailing commas and reports duplicate object keys as an error.
• Can sort object keys alphabetically.
• Prefers using the 8x faster native JSON parser, if possible.
• Depends on up-to-date npm modules with no installation warnings.

Requires grunt 1.0+ and node 4.0+.

Installation

npm i @prantlf/grunt-jsonlint -D

Configuration

Add the following (multi-)task to your Gruntfile:

jsonlint: {
  sample: {
    src: [ 'some/valid.json' ],
    options: {
      formatter: 'prose'
    }
  }
}

Add the following to load the task into your Gruntfile:

grunt.loadNpmTasks('@prantlf/grunt-jsonlint');

An error will be thrown if the JSON file contains syntax errors. To prefer an error format compatible with Visual Studio, change the formatter to 'msbuild'.

Customizing

There is a couple of options, which can support non-standard JSON syntax, usually used in configuration files for convenience:

jsonlint: {
  all: {
    src: [ 'some/settings.json' ],
    options: {
      mode: 'json',
      ignoreComments: false,
      ignoreTrailingCommas: false,
      allowSingleQuotedStrings: false,
      allowDuplicateObjectKeys: true,
    }
  }
}

• mode, when set to "cjson" or "json5", enables some other flags automatically
• ignoreComments, when true JavaScript-style single-line and multiple-line comments will be recognised and ignored
• ignoreTrailingCommas, when true trailing commas in objects and arrays will be ignored
• allowSingleQuotedStrings, when true single quotes will be accepted as alternative delimiters for strings
• allowDuplicateObjectKeys, when false duplicate keys in objects will be reported as an error

Formatting

Add the following (multi-)task to your Gruntfile:

jsonlint: {
  all: {
    src: [ 'some/valid.json' ],
    options: {
      format: true,
      indent: 2,
      sortKeys: false
    }
  }
}

• format, when true JSON.stringify will be used to format the JavaScript (if it is valid)
• indent, the value passed to JSON.stringify, it can be the number of spaces, or string like "\t"
• sortKeys, when true keys of objects in the output JSON will be sorted alphabetically (format has to be set to true too)

Schema Validation

You can validate JSON files using JSON Schema drafts 04, 06 or 07:

jsonlint: {
  all: {
    src: [ 'some/manifest.json' ],
    options: {
      schema: {
        src: 'some/manifest-schema.json',
        environment: 'json-schema-draft-04'
      }
    }
  }
}

• schema, when set the source file will be validated using ae JSON Schema in addition to the syntax checks
• src, when filled with a file path, the file will be used as a source of the JSON Schema
• environment, can specify the version of the JSON Schema draft to use for validation: "json-schema-draft-04", "json-schema-draft-06" or "json-schema-draft-07" (if not set, the schema draft version will be inferred automatically)

Reporting

There are a few options available for reporting errors:

Error Message Format

The standard error message format (prose) is optimized for human reading and looks like:

>> File "test/invalid.json" failed JSON validation at line 9.

This is customizable to conform to the Visual Studio style by specifying the formatter option as msbuild, like:

jsonlint: {

  visualStudioExample: {
    src: [ 'test/invalid.json' ],
    options: {
      formatter: 'msbuild'
    }
  }

}

The output will look like:

>> test/invalid.json(9): error: failed JSON validation

Error Reporting

By default, the raw error from the underlying jsonlint library comes through to the grunt output. It looks like:

Error: Parse error on line 9:
...        "2"        "3",      ],      
----------------------^
Expecting 'EOF', '}', ':', ',', ']', got 'STRING'

To customize this, change the reporter option to jshint (the format is inspired by how jshint formats their output, hence the name):

jsonlint: {

  jshintStyle: {
    src: [ 'test/invalid.json' ],
    options: {
      reporter: 'jshint'
    }
  }

}

The output will look like:

 9 |  "3"
      ^ Expected 'EOF', '}', ':', ',', ']' and instead saw '3'

The default reporter is called exception since it simply relays the raw exception.

Running Tests

Unit tests are provided for automated regression testing. The easiest way to run them is with:

npm test

Alternatively, if you have grunt-cli installed, you could use grunt directly:

grunt test

Which does the same thing.

Release History

• 2013-02-20 v1.0.0 First official release
• 2015-10-29 v1.0.6 CJSON support thanks to @fredghosn, unit tests
• 2016-05-27 v1.0.8 Option to format JSON file thanks to @robblue2x
• 2016-06-11 v1.1.0 Enhanced error reporting for better human reading and Visual Studio integration.
• 2019-05-27 v1.2.0 Support comments, single-quoted strings and JSON Schema validation
• 2019-05-30 v1.3.0 Support object keys sorting in the formatted output
• 2019-05-30 v1.3.1 Prefer faster native JSON parser, fix error reporting
• 2019-06-02 v2.0.0 Upgrade to @prantlf/jsonlint using a hand-built parser instead of the Jison-generated one with additional options

License

Copyright (C) 2013-2019 Brandon Ramirez, Ferdinand Prantl

Licensed under the MIT license.