Property 4 JSON

Build script to automatically enrich static files containing JavaScript objects with auto-incremented properties without the need of a database.

What this library can do:

• add (autoincrement) properties to each object in a JSON-like structure
• quickly process large folders containing many static files
• match specific file types by file pattern
• unify unordered or scattered property values to a sequential order across objects of the same level

Why this library is useful:

• it works with any file type, i.e. .js, .ts or .json
• it does not reformat your file and it preserves whitespaces and respects your indentation
• it does not require valid JSON structures as it is RegExp based
• it is idempotent (multiple executions will not have any other effect as the initial execution)

Setup

Install the lib via npm i property-4-json -D as dev dependency and add the following line to your npm scripts:

"scripts": {
    "autoincrement-ids": "node node_modules/property-4-json --folder=dir/subdir --filetype=.json"
}

Now you can run the the script using

npm run autoincrement-ids

Options

Pass each option using following syntax --option=value

• folder directory of the source files relative to your package.json, i.e. --folder=assets/files
• filetype optional, change the file type, i.e. .js, .ts, .json etc. of which JSON is default
• prop optional, the property name that should be auto incremented, id is default
• quotation optional, quotation type in which the parameter should be wrapped, possible values are none, single and double (default)
• stopwords optional, list of comma separated stopwords, i.e. --stopwords=import,export - will not match an object if a stopword is ahead the opening bracket
• startvalue optional, start value of incremental variable other than 0 - the value will keep incrementing across multiple matched files
• delimiter optional, changes the key-value delimiter from colon to custom character, i.e. setting --delimiter='=' will make use of = symbol

Examples

Running the algorithm on the following JSON file containing an array of objects

[
  {
    "foo": { },
    "bar": []
  },
  {
    "bar" : {
      "baz" : false
    }
  }
]

will enrich each object with an incremental id after the opening bracket

[
  {
    "id": 0, // <- here
    "foo": { },
    "bar": []
  },
  {
    "id": 1, // <- and here
    "bar" : {
      "baz" : false
    }
  }
]

You are not limited to JSON files, the algorithm can be applied to any structure wrapped in curly brackets. Using the algorithm with with following parameters on a typescript file

node node_modules/property-4-json --folder=dir/subdir --filetype=.ts --prop=count --quotation=none --delimiter=' =' --stopwords=interface,export --endline=semicolon

class Car {
  engine: Engine;
  cylinders: number;
}
export { Car };

will result in

class Car {
  count = 0; // <- here
  engine: Engine;
  cylinders: number;
}
export { Car };

regardless how many class objects are contained across all files, each will be incremented with its own unique count variable. Curly braced objects after statements like export, interface etc. will be omitted.

Updating existing properties

If your object already contains the property that you want to increment, the script will recognize the property and update it with a new value. Multiple executions of the script on the same file will not have any negative effect.

{"id": 999, "car": true}, {"vehicle": false, "id": 155}

would be updated by id while keeping the formatting as

{"id": 0, "car": true}, {"vehicle": false, "id": 1}

no matter how often the script is applied on that file.

Limitations

• this lib is not meant to replace a database autoincrement feature, it was developed to clean up static data before a production build
• this lib can be used for enriching existent dummy data with incremental properties, if you look for a solution to maintain JSON data try TODO json-server
• if you look for a way to create dummy data that already contains id fields, try Mockaroo

Upcoming features

• add new properties at lower nesting levels than 1 (currently the RegExp will always match the first opening bracket of the object)
• pass one filename instead of a file pattern or folder name

Contributing

Please report bugs in the issues section

Author & License

• Jan Suwart | MIT License