johnste/getify

A utility to grab nested values from objects.

Getify

A utility to grab nested values from objects. Like lodash's _.get, or countless other variants. Getify uses ES6 proxies to enable usage without string or array paths.

How to use

import getify from 'getify'

const obj = {
  a: {
  	b: ['c', 'd'],
  	e: ['f', 'g']
  }
}

// Get existing value from object
getify(obj).a.b[1]() // returns "d"

// Get undefined if path doesn't exist
getify(obj).nothing.here() // returns undefined

// Use a default value if path doesn't exist
getify(obj).nothing.here('oops!') // returns "oops!"

Advanced usage

const obj = {
  a: {
  	b: ['c', 'd', 'e'],
  	f: {0: 'g', 1: 'h'},
  }
}

// Save intermediate values paths (object destructuring works fine)
const { f, b } = getify(obj).a
b[1]() // returns 'd'
f[0]() // returns 'g'

// Use getify.all to get all properties on the current path
getify(obj).a[getify.all][1]() // returns ['d', 'h']
getify(obj).a[getify.all]() // returns [['c', 'd', 'e'], {0: 'g', 1: 'h'}]

// Use getify.first to get first property on the current path
getify(obj).a[getify.first][1]() // returns 'd'

// Use getify.first to get first property on the current path
getify(obj).a[getify.last][1]() // returns 'h'

// Or combine them
getify(obj).a[getify.all][getify.last]() // returns ['e', 'h']

Browser and server support

ES6 Proxy is currently supported by the latest stable version of Chrome, Firefox and Edge. It's also supported by Node 6.x. Safari doesn't support Proxies.

ES6 compatibility table: Proxy

Install

npm install getify

API

Get a path from a value

getify(value).any.path['here'][3](defaultValue)

value is any valid javascript value: objects, strings, arrays, numbers. The path is any valid javascript path. If the path is not available in the object, getify will return undefined or the default value. If the path exists and contains the value undefined, that will be returned regardless of the default value provided.

Symbols

getify.all - get all keys on the current object. If there are no keys, this will result in an empty array

getify.first - get the first key on the current object. The key is the first one returned from Object.keys

getify.last - get the last key on the current object. The key is the last one returned from Object.keys

A note on performance

Currently Getify is around 1-3 times slower than lodash _.get for simpler use cases in Chrome, and around 15-20 times slower in Firefox. Currently using getify is a two step process where the accessing paths on the Getified object creates a path in an array. When you execute the returned function Getify finds the nested value in the object in a way that's very close to how _.get works. I've been fiddling around trying to make this process go faster but my attempts thus far have had worse performance than the current one.