trim-apply

Drops undefined arguments from the end of a function call.

Useful if you’re forwarding arguments from one function to another, but the second function has behavior which is affected by the presence of an explicit undefined argument.

Accepts an array of arguments, just like Function.prototype.apply(). If you want to provide an argument list instead, use the trim-call module.

Installation

Requires Node.js 5.0.0 or above.

npm i trim-apply

API

The module exports a function (trimApply()) that has one other function attached to it as a method (trimApply.new()).

trimApply()

Parameters

1. fn (function): The function to call.
2. thisArg (any): The value of this while the function is being called.
3. args (array): The arguments for the function call. Any undefined arguments at the end will be dropped.

Return Value

The return value of fn when called with thisArg and args.

trimApply.new()

Parameters

1. Cls (class): The class whose constructor you want to call.
2. args (array): The arguments for the constructor call. Any undefined arguments at the end will be dropped.

Return Value

A new instance of Cls constructed with args.

Examples

const trimApply = require('trim-apply')

f1('test')

function f1 (a, b) {
  trimApply(f2, this, [a, b])
}

function f2 () {
  arguments.length // 1
}

Because of trimApply(), the f2() function only receives one argument.

Here is the above example repeated without trimApply():

f1('test')

function f1 (a, b) {
  f2.apply(this, [a, b])
}

function f2 () {
  arguments.length // 2
}

Without trimApply(), the undefined b argument of f1() becomes an explicit second argument for f2().

Related

• trim-call