rhythnic / dead-leaves

Immutably prune a nested JavaScript object.

Dead Leaves

A utility for using a filter function to prune JavaScript objects

Install

npm install --save dead-leaves

Usage

import { prune } from 'dead-leaves'

const obj = {
  name: 'Bud',
  age: '',
  friends: []
}

const nextObj = prune(obj)

// data transformation is immutable
console.log(nextObj === obj) // false

// the default filter function removes all null or empty values
console.log(nextObj)
// {
//   name: 'Bud'
// }

How it works

Prune is called with data and a filter function. If you don't include a filter function, the default is used, which is called 'isNotNilOrEmpty'. You can also import isNotNilOrEmpty from dead-leaves. Each value is evaluated after it's children have been evaluated. In the case of isNotNilOrEmpty, if an object or array are empty after their children have been evaluated, they will also be removed. The passing values are copied into a new object, so the data is immutable. The parent object is always returned even if it fails the filter function.

Custom filter function

import { prune, isNotNilOrEmpty } from 'dead-leaves'

// removes: 2, null, undefined, '', {}, []
const filterFn = value => {
  return value !== 2 && isNotNilOrEmpty(value)
}

const nextObj = prune(obj, filterFn)