pure-object

Create objects with no inhereted prototype

Table of Contents

• Installation
• Usage
  • Signature
• Benefits
• Browser support
• Development

Installation

$ npm i pure-object --save

Usage

// ES2015
import pure from "pure-object";

// CommonJS
const pure = require("pure-object").default;

// script
var pure = window.pureObject.default;

const objectToPurify = {
  foo: "bar"
};

// create an object with no prototype
const pureObject = pure(objectToPurify);

console.log(pureObject); // {foo: 'bar'}
console.log(object.toString); // [Function]
console.log(pureObject.toString); // undefined
console.log(Object.getPrototypeOf(pureObject)); // null

// create an object with only the prototypical methods you pass
const pureObjectWithProto = pure(objectToPurify, {
  bar() {
    console.log("baz");
  }
});

console.log(Object.getPrototypeOf(pureObject)); // {bar: [Function]}
console.log(object.toString); // [Function]
console.log(pureObject.toString); // undefined (bar is the only method on the prototype)

Signature

pure(object: Object, prototype: Object)

• object
  • Object whose key / value pairs will be shallow-cloned to the pure object with same property descriptor
  • Clones both enumerable and non-enumerable properties (uses getOwnPropertyNames and getOwnPropertySymbols)
• prototype
  • Object whose key / value pairs will be assigned to the pure object's prototype (if not passed, prototype is null)
  • Clones both enumerable and non-enumerable properties (uses getOwnPropertyNames and getOwnPropertySymbols)

Benefits

1. Tinier footprint (memory allocation is smaller than the standard object's)
2. More logical looping (no need to check hasOwnProperty in for-in loops)
3. Simplified prototypical chain (only the methods you explicitly set will be on the prototype)

It is very likely that a vast majority of your objects could be made into pure objects and you would never notice the difference.

Browser support

• Chrome (all versions)
• Firefox (all versions)
• Edge (all versions)
• Opera 15+
• IE 9+
• Safari 6+
• iOS 8+
• Android 4+

Development

Standard stuff, clone the repo and npm install dependencies. The npm scripts available:

• build => run webpack to build development dist file with NODE_ENV=development
• build:minified => run webpack to build production dist file with NODE_ENV=production
• dev => run webpack dev server to run example app / playground
• dist => runs build and build:minified
• lint => run ESLint against all files in the src folder
• prepublish => runs prepublish:compile when publishing
• prepublish:compile => run lint, test:coverage, transpile:es, transpile:lib, dist
• test => run AVA test functions with NODE_ENV=test
• test:coverage => run test but with nyc for coverage checker
• test:watch => run test, but with persistent watcher
• transpile:lib => run babel against all files in src to create files in lib
• transpile:es => run babel against all files in src to create files in es, preserving ES2015 modules (for pkg.module)