https://github.com/samouri/arity

a tiny library for reliably determining arity
https://github.com/samouri/arity

Last synced: about 2 months ago
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a tiny library for reliably determining arity

• Host: GitHub
• URL: https://github.com/samouri/arity
• Owner: samouri
• Created: 2017-11-28T00:01:52.000Z (over 8 years ago)
• Default Branch: master
• Last Pushed: 2017-11-28T21:19:51.000Z (over 8 years ago)
• Last Synced: 2025-10-23T04:37:41.796Z (8 months ago)
• Language: JavaScript
• Homepage:
• Size: 26.4 KB
• Stars: 2
• Watchers: 1
• Forks: 1
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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README

          
arity 

=====

[![CircleCI](https://circleci.com/gh/samouri/arity.svg?style=svg)](https://circleci.com/gh/samouri/arity)

> In logic, mathematics, and computer science, the arity /ˈærɪti/ of a function is the number of arguments or operands that the function takes.

Sometimes you want to be able to tell how many arguments a function takes.

99% of the time you can do something as simple as calling `fn.length` -- but this will not work if a function accesses the [arguments](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/arguments) object directly.

This module will even return the correct number of arguments to expect for those tricky cases.

### Install

```bash

npm install --save-dev arity

```

### To use

```javascript

const arity = require('arity');

function doSomething(arg1, arg2) { ... }

const arityOfDoSomething = arity(doSomething); // value will be 2

```