@prantlf/gulp-jsonlint

JSON/JSON5 file syntax validation plugin for Gulp using JSONLint

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

• Validates with both JSON and JSON5 standards.
• Supports JSON Schema drafts 04, 06, 07, 2019-09 and 2020-12.
• Supports JSON Type Definition.
• 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.
• Offers pretty-printing including comment-stripping and object keys without quotes (JSON5).
• Prefers using the 7x faster native JSON parser, if possible.
• Optionally reformats the output JSON and sorts object keys alphabetically.
• Offers alternative error location formatters and message reporters.
• Depends on up-to-date npm modules with no installation warnings.

Usage

First, install @prantlf/gulp-jsonlint as a development dependency:

npm i -D @prantlf/gulp-jsonlint

Then, add it to your gulpfile.js:

var jsonlint = require("@prantlf/gulp-jsonlint");

gulp.src("./src/*.json")
    .pipe(jsonlint())
    .pipe(jsonlint.reporter());

Using a custom reporter:

var jsonlint = require('@prantlf/gulp-jsonlint');
var log = require('fancy-log');

var myCustomReporter = function (file) {
    log('File ' + file.path + ' is not valid JSON.');
};

gulp.src('./src/*.json')
    .pipe(jsonlint())
    .pipe(jsonlint.reporter(myCustomReporter));

Using an alternative error location formatter and error message reporter:

var jsonlint = require('@prantlf/gulp-jsonlint');

gulp.src('./src/*.json')
    .pipe(jsonlint({
        formatter: 'msbuild', // prose or msbuild
        reporter: 'jshint'    // exception or jshint
    }))
    .pipe(jsonlint.reporter(myCustomReporter));

API

jsonlint(options)

Options can be passed as keys in an object to the jsonlint function. The following are their defaults:

jsonlint({
    // parsing
    mode: 'json',
    ignoreComments: false,
    ignoreTrailingCommas: false,
    allowSingleQuotedStrings: false,
    allowDuplicateObjectKeys: true,
    // formatting
    format: false,
    prettyPrint: false,
    indent: 2,
    sortKeys: false,
    pruneComments: false,
    stripObjectKeys: false,
    enforceDoubleQuotes: false,
    enforceSingleQuotes: false,
    trimTrailingCommas: false
})

• 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

• format, when true JSON.stringify will be used to format the JavaScript (if it is valid)

• prettyPrint, 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)

• pruneComments, when true comments will be omitted from the prettified output (CJSON feature, prettyPrint has to be set to true)

• stripObjectKeys, when true quotes surrounding object keys will be stripped if the key is a JavaScript identifier name (JSON5 feature, prettyPrint has to be set to true)

• enforceDoubleQuotes, when true string literals will be consistently surrounded by double quotes (JSON5 feature, prettyPrint has to be set to true)

• enforceSingleQuotes, when true string literals will be consistently surrounded by single quotes (JSON5 feature, prettyPrint has to be set to true)

• trimTrailingCommas, when true trailing commas after all array items and object entries will be omitted (JSON5 feature, prettyPrint has to be set to true)

Schema Validation

You can validate JSON files using JSON Schema drafts 04, 06, 07, 2019-09 or 2020-12, or using JSON Type Definition if you specify the schema in addition to other options:

jsonlint({
  schema: {
    src: 'some/manifest-schema.json',
    environment: '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 one or more file paths, the files will be used as a source of the JSON Schema
• environment, can specify the version of the JSON Schema draft to use for validation: "draft-04", "draft-06", "draft-07", "draft-2019-09", "draft-2020-12" or "jtd" (if not set, the supported schema draft versions will be 06 and 07)

jsonlint.reporter(customReporter)

customReporter(file)

Type: function

You can pass a custom reporter function. If ommited then the default reporter will be used.

The customReporter function will be called with the argument file.

file

Type: object

This argument has the attribute jsonlint which is an object that contains a success boolean attribute. If it's false you also have a message attribute containing the jsonlint error message.

jsonlint.reporter(options)

options

Type: object: { formatter, reporter }

If you pass an object to reporter, the default reported will not be used. There will be two optional string properties recognized in the object - formatter and reporter. The report will be divided to two parts - the single-line error location (for the formatter) and the rest of the error message (for the reporter). The two parts will be handled by the chosen formatter and reporter.

Formatter	Description
prose	Writes a sentence with the file name and the line and column of the error occurrence (default)
msbuild	Mimics the format of the first line of the error report printed by MS Visual Studio

Reporter	Description
exception	Writes the original message returned by jsonlint (default)
jshint	Mimics the format of the error report printed by jshint

jsonlint.failOnError()

Stop a task/stream if an jsonlint error has been reported for any file.

// Cause the stream to stop(/fail) before copying an invalid JS file to the output directory
gulp.src('**/*.js')
	.pipe(jsonlint())
	.pipe(jsonlint.failOnError())
	.pipe(gulp.dest('../output'));

jsonlint.failAfterError()

Stop a task/stream if an jsonlint error has been reported for any file, but wait for all of them to be processed first.

Examples

The following examples can be tested and the console output observed by using the sample gulpfile.js in this repository. All of them can be run by npm run examples:

Successful JSON file validation:

$ gulp valid
[06:59:17] Using gulpfile .../gulp-jsonlint/gulpfile.js
[06:59:17] Starting 'valid'...
[06:59:17] Finished 'valid' after 15 ms

Validation stopped immediately after the first error occurred, plain error printed as returned by jsonlint, no colouring:

$ gulp one
[06:59:17] Using gulpfile .../gulp-jsonlint/gulpfile.js
[06:59:17] Starting 'one'...
[06:59:17] 'one' errored after 17 ms
[06:59:17] JSONLintError in plugin "gulp-jsonlint"
Message:
    Parse error on line 2, column 14:
{    "key1": forgotquotes    "key...
--------------^
Unexpected token o
Details:
    domain: [object Object]
    domainThrown: true

Validation stopped after printing all validation failures, the default (single) error reporter used, colouring enabled:

$ gulp two
[06:59:18] Using gulpfile .../gulp-jsonlint/gulpfile.js
[06:59:18] Starting 'two'...
[06:59:18] Error on file .../gulp-jsonlint/test/fixtures/comments.json
[06:59:18] Parse error on line 1, column 1:
/* Commented configu...
^
Unexpected token /
[06:59:18] 'two' errored after 25 ms
[06:59:18] JSONLintError in plugin "gulp-jsonlint"
Message:
    Failed with 1 error
Details:
    domain: [object Object]
    domainThrown: true

Validation stopped after printing all validation failures, the default (separate) formatter and reporter used, colouring enabled:

$ gulp three
[06:59:18] Using gulpfile .../gulp-jsonlint/gulpfile.js
[06:59:18] Starting 'three'...
[06:59:18] File test/fixtures/json5.json failed JSON validation at line 2, column 5.
{    // String parameter...
-----^
Unexpected token /
[06:59:18] 'three' errored after 17 ms
[06:59:18] JSONLintError in plugin "gulp-jsonlint"
Message:
    Failed with 1 error
Details:
    domain: [object Object]
    domainThrown: true

Validation stopped after printing all validation failures, the msbuild formatter and jshint reported used, colouring enabled:

$ gulp all
[06:59:19] Using gulpfile .../gulp-jsonlint/gulpfile.js
[06:59:19] Starting 'all'...
[06:59:19] test/fixtures/comments.json(1,1): error: failed JSON validation
     1 | /* Commented configu...
         ^ Unexpected token /
[06:59:19] test/fixtures/invalid.json(2,14): error: failed JSON validation
     2 | ..."key1": forgotquo...
                     ^ Unexpected token o
[06:59:19] test/fixtures/json5.json(2,5): error: failed JSON validation
     2 | {    // String param...
              ^ Unexpected token /
[06:59:19] test/fixtures/single-quotes.json(2,5): error: failed JSON validation
     2 | {    'key1': 'value'...
              ^ Unexpected token '
[06:59:19] test/fixtures/trailing-commas.json(3,1): error: failed JSON validation
     3 | ... "value",}
                     ^ Unexpected token }
[06:59:19] 'all' errored after 32 ms
[06:59:19] JSONLintError in plugin "gulp-jsonlint"
Message:
    Failed with 5 errors
Details:
    domain: [object Object]
    domainThrown: true

License

Copyright (C) 2013-2023 Rogério Vicente, Ferdinand Prantl

Licensed under the MIT License.