@blakek/deep

deep

🐡 Get, set, remove, and test for deeply nested properties

Helps you safely work with nested properties.

Install

Using Yarn:

$ yarn add @blakek/deep

…or using npm:

$ npm i --save @blakek/deep

Usage

import { clone, get, getOr, has, omit, pluck, remove, set } from '@blakek/deep';

const user = {
  id: 'abf87de',
  roles: ['alert:create', 'alert:read'],
  sites: {
    github: {
      username: 'blakek'
    }
  }
};

// Deeply clone most values
const userCopy = clone(user);
user === userCopy; //» false
user.id === userCopy.id; //» true
user.roles === userCopy.roles; //» false
user.roles[0] === userCopy.roles[0]; //» true

// Get a property value
get('sites.github.username', user); //» 'blakek'

// Arguments can be partially applied
const githubUsername = get('sites.github.username');
githubUsername(user); //» 'blakek'

// Get a property value with a fallback other than `undefined`
getOr('no-account', 'sites.facebook.username', user); //» 'no-account'

// Test for a property value
has('sites.github', user); //» true

// Clone an object and omit properties
omit(['roles', 'sites'], user); //» { id: 'abf87de' }

// Pluck a subset of properties
pluck(['id', 'roles'], user);
//» { id: 'abf87de', roles: [ 'alert:create', 'alert:read' ] }

// Remove a property value, modifying the current object
remove('a', { a: 42, b: 123 }); //» { b: 123 }

// Set a property value, modifying the current object
set(123, 'a.b.c', { a: 42 }); //» { a: { b: { c: 123 } } }

API

For all these:

• path can be either a dot-notation string or array of path parts
• arguments can be partially applied

clone

Returns a deep clone / deep copy of most values: primitive values, objects, arrays, Map, Set, Date, etc.

function clone<T extends unknown>(value: T): T;

const object = { value: 'yep' };
const cloned = clone(object);

cloned === object; //» false
cloned.value === object.value; //» true

get

Gets the value for a given path with an optional fallback value.

function get(path: Path, object: any): any;

const user = {
  id: 'abf87de',
  roles: ['alert:create', 'alert:read'],
  sites: {
    github: {
      username: 'blakek'
    }
  }
};

get('id', user); //» 'abf87de'
get('roles.0', user); //» 'alert:create'
get('roles[0]', user); //» 'alert:create'
get(['roles', 1], user); //» 'alert:read'
get('sites.github.username', user); //» 'blakek'

const getID = get('id');
getID(user); //» 'abf87de'

getOr

Like get, gets a value from an object. Will return a fallback other than undefined if the value was not found equal to undefined.

function getOr(defaultValue: any, path: Path, object: any): any;

const user = {
  id: 'abf87de',
  roles: ['alert:create', 'alert:read'],
  sites: {
    github: {
      username: 'blakek'
    }
  }
};

getOr('/images/placeholder.png', 'sites.github.image', user); //» '/images/placeholder.png'

const getRoles = getOr([], 'roles');
getRoles(user); //» ['alert:create', 'alert:read']
getRoles({}); //» []

has

Returns true if a value was found at the given path or false if nothing was found.

function has(path: Path, object: any): boolean;

const product = {
  id: 'abf87de',
  name: 'Logo T-Shirt',
  attributes: {
    isCool: undefined,
    materials: ['cotton']
  }
};

has('attributes.materials', product); //» true
has(['avability', 'sizes'], product); //» false
has('attributes.isCool', product); //» true; property exists but is undefined

// `get()` should be used if you want to ensure a value is not `undefined`
getOr(false, 'attributes.isCool', product); //» false

omit

Returns a clone of an object with some properties removed.

Note: omit() returns a clone with properties removed. If you'd rather modify the existing object for performance, consider using remove().

function omit(properties: Path[], object: any): any;

const user = {
  username: 'blakek',
  roles: ['alert:create', 'alert:read'],
  sites: {
    github: {
      username: 'blakek'
    }
  }
};

omit(['roles', 'sites'], user); //» { username: 'blakek' }
omit(['username', 'roles', 'sites.doesnt.exist'], user);
//» { sites: { github: { username: 'blakek' } } }

pluck

Gets a subset of properties from an object.

function pluck(properties: Path[], object: any): any;

const user = {
  username: 'blakek',
  roles: ['alert:create', 'alert:read'],
  sites: {
    github: {
      username: 'blakek'
    }
  }
};

pluck(['username'], user); //» { username: 'blakek' }
pluck(['username', 'roles'], user);
//» { username: 'blakek', roles: [ 'alert:create', 'alert:read' ] }

remove

Removes a value at a path and returns the object.

Note: remove() modifies the passed-in object rather than creating a copy. If you'd rather return a new object:

• use omit(); omit() returns a clone with a list of properties removed
• use clone() before remove()
• consider another solution (unchanged is really good)

function remove(path: Path, object: any): any;

const user = {
  username: 'blakek',
  password: 'wouldntyouliketoknow'
};

remove('password', user); //» { username: 'blakek' }
remove('property.does.not.exist', user);
//» { username: 'blakek' } (same object from previous line)

set

Sets a value at a path and returns the object.

Note: set() modifies the passed-in object rather than creating a copy. If you'd rather return a new object:

• use clone() before set()
• consider another solution (unchanged is really good)

function set(value: any, path: Path, object: any): any;

const user = {
  profile: {
    bgColor: '#639'
  }
};

set('tomato', 'profile.bgColor', user); //» { profile: { bgColor: 'tomato' } }

set('/images/user.png', 'profile.bgImage', user);
//» { profile: { bgColor: 'tomato', bgImage: '/images/user.png' } }

const logout = set(null, 'profile');
logout(user); //» { profile: null }

Contributing

Node.js and Yarn are required to work with this project.

To install all dependencies, run:

yarn

Useful Commands

yarn build	Builds the project to ./dist
yarn format	Format the source following the Prettier styles
yarn test	Run project tests
yarn test --watch	Run project tests, watching for file changes

License

MIT