modify-json-loader

Modifies JSON before passed to json-loader. Based on json-pointer

Usage

install via npm:

npm install --save-dev modify-json-loader

add to webpack config:

module: {
    rules: [
        {
            test: /package\.json/,
            use: [
                'json-loader',
                {
                    loader: 'modify-json-loader',
                    options: {
                        include: '/address/city'
                    }
                }
            ]
        }
    ]
}

Pointers

This loader uses JSON pointer to address specific properties in JSON.

/* json */                     /* pointer */
{
  "foo": "bar",                /foo
  "list": [                    /list
    "entry0",                  /list/0
    123                        /list/1
  ],
  "language": {                /language
    "en": "example",           /language/en
    "de": "Beispiel",          /language/de
  }
}

For more details see JSON-pointer specification

Options

.include

Type:    pointer || [pointer]
Default: undefined

If set, only properties matching the pointers are written into output result.

include: ['/foo', '/language/de']
	=>
{
  "foo": "bar",
  "language": {
    "de": "Beispiel",
  }
}

.exclude

Type:    pointer || [pointer]
Default: undefined

If set, only properties not matching the pointers are written into output result.

exclude: ['/language/de', '/list']
	=>
{
  "foo": "bar",
  "language": {
    "en": "example",
  }
}

Note: including or excluding array elements is not working properly at the moment.

.set

Type:    object
Default: undefined

The set options allows to change or create new properties for the output JSON. The parameter for this option is an object containing key/value pairs, where the keys represent JSON pointers which are set to the related values. Following types are allowed for values:

• string, number, boolean, null: set the pointer to the value
• object: set the pointer to the whole object
• function(originalValue, originalJSON): set the pointer to the result of a provided function. The function is invoked with two parameters:
  • originalValue: the value found in the original json for that pointer. undefined if pointer does not exist in original JSON.
  • originalJSON: the original JSON object

set: {
  '/foo': (val, json) => `Bier${val}`,
  '/time': () => new Date(),
  '/list/1': (val) => val * 2,
  '/language/de': 'beispiellos',
}
	=>
{
  "foo": "Bierbar",
  "time": "2017-07-23T00:48:34.683Z",
  "list": [
    "entry0",
    246
  ],
  "language": {
    "en": "example",
    "de": "beispiellos",
  }
}

.stringified

Type: boolean
Default: false

If not set, the loader outputs the manipulated JSON as a plain java object. If set to true, the output is a converted to a JSON string.

.disableCaching

Type: boolean
Default: false

If set to true the loader will prevent webpack from caching its result. This is useful if your are using the the .set option in combination with a function providing dynamic results for repeated runs.

set: {
  '/time': () => new Date(),
},
disableCaching: true