@activeprospect/old
v1.1.5
Published
Make the 'new' keyword optional for ES6 classes
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old
Make the 'new' keyword optional for ES6 classes
Usage
npm install old
var old = require('old')
class Class {
// ...
}
var Class2 = old(Class)
Class() // throws error
Class2() // creates an instance of Class
Rationale
With ES5 "constructor" functions, a common pattern is to make the new
keyword optional by doing something like the following:
function Foo () {
if (!(this instanceof Foo)) return new Foo()
// do constructor stuff
}
Recently, ES6 introduced classes to replace constructor functions. However, if these classes are instantiated without new
, an error is thrown: TypeError: Class constructor Foo cannot be invoked without 'new'
. This module makes new
optional, even for these ES6 classes.
Credit
- Thank you to Sorella in ##javascript (Freenode) for the clean solution
- Thanks to slikts in ##javascript for the name idea