onetime 

Ensure a function is only called once

When called multiple times it will return the return value from the first call.

*Unlike the module once, this one isn't naughty and extending Function.prototype.*

Install

$ npm install onetime

Usage

js
const onetime = require('onetime');

let i = 0;

const foo = onetime(() => ++i);

foo(); //=> 1
foo(); //=> 1
foo(); //=> 1

onetime.callCount(foo); //=> 3

js
const onetime = require('onetime');

const foo = onetime(() => {}, {throw: true});

foo();

foo();
//=> Error: Function `foo` can only be called once

API

onetime(fn, options?)

Returns a function that only calls fn once.

fn

Type: Function

Function that should only be called once.

options

Type: object

throw

Type: boolean\ Default: false

Throw an error when called more than once.

onetime.callCount(fn)

Returns a number representing how many times fn has been called.

Note: It throws an error if you pass in a function that is not wrapped by onetime.

js
const onetime = require('onetime');

const foo = onetime(() => {});

foo();
foo();
foo();

console.log(onetime.callCount(foo));
//=> 3

fn

Type: Function

Function to get call count from.

onetime for enterprise

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