# wfn

> Gives a wrapper function the properties and string value of its underlying function.

Latest version **1.0.0** (published 2018-02-03) · MIT license · 0 weekly downloads

## Install

```sh
npm install wfn
pnpm add wfn
yarn add wfn
bun add wfn
```

## Health

**Score 15/100 (F)** — status: abandoned.

Positive: no vulnerabilities.

Warnings: low downloads; no types; no esm support.

Negative: abandoned; low maintenance score.

## Facts

| | |
|---|---|
| Version | 1.0.0 |
| Published | 2018-02-03 |
| First published | 2018-02-03 |
| Weekly downloads | 0 |
| License | MIT |
| TypeScript types | none |
| Module format | CommonJS |
| Node | >=6.0.0 |
| Dependencies | 3 |
| Known vulnerabilities | 0 |
| Install scripts | no |
| GitHub stars | 1 |
| Author | John Lamansky |
| Maintainers | lamansky |
| Keywords | wrapper, function, properties, toString |

## Links

- npm: https://www.npmjs.com/package/wfn
- Repository: https://github.com/lamansky/wfn
- Issues: https://github.com/lamansky/wfn/issues
- npm.io page: https://npm.io/package/wfn

## Dependencies (3)

- [sorp](https://npm.io/package/sorp.md) ^1.0.0
- [copy-own](https://npm.io/package/copy-own.md) ^1.0.0
- [english-list](https://npm.io/package/english-list.md) ^1.0.0

## Alternatives

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## Recent versions

- 1.0.0 (latest) — 2018-02-03

## README

# wfn

A module that prepares Wrapper Functions.

Ensures your wrapper has the same properties as the underlying function, such as `name` and `length`. When `toString()` is called on the wrapper function, the code of the original function is shown, together with a comment identifying the wrapper(s).

## Installation

Requires [Node.js](https://nodejs.org/) 6.0.0 or above.

```bash
npm i wfn
```

## API

The module exports a single function.

### Parameters

1. `fn` (Function): The underlying function
2. `wrapper` (Function): The wrapper function that calls `fn`

### Return Value

The modified `wrapper` function

## Usage

```javascript
const wfn = require('wfn')

function func (a, b, c) { return 'result' }
function wrapper () { return func() }

wrapper() // 'result'

// Before
wrapper.name // 'wrapper'
wrapper.length // 0
wrapper.toString() // 'function wrapper () { return func() }'

// Apply the module
wfn(func, wrapper)

// After
wrapper.name // 'func'
wrapper.length // 3
wrapper.toString() // 'function func (a, b, c) { return 'result' } /* [wfn] Wrapped with wrapper() */'
```

### Wrapper Function Stringification

In the above example, note that the wrapper’s `toString()` method produces the code of the underlying function — not of the wrapper — but with a comment notation that the function has been wrapped.

If you wrap a function more than once, `wfn` will recognize this and will generate a comment notation that mentions all the wrappers. Consider the following example:

```javascript
function original () {
  return 'value'
}

const wrapper1 = wfn(original, function wrapper1 () { return original() })
const wrapper2 = wfn(wrapper1, () => wrapper1())
const wrapper3 = wfn(wrapper2, function wrapper3 () { return wrapper2() })
```

If you call `wrapper3.toString()`, you will get the following:

```
function original () {
  /* [wfn] Wrapped with wrapper1(), wrapper3(), and 1 other unnamed function */
  return 'value'
}
```

If this is something you absolutely don’t care about, and you only want properties like `name` and `length` copied, consider swapping out this module for [`copy-own`](https://github.com/lamansky/copy-own) so you have less overhead.

## Related Modules

For more projects like this, check out the [xfn](https://github.com/lamansky/xfn) family of modules.

---
_Source: https://npm.io/package/wfn · Machine-readable twin of the npm.io package page. Health data is recomputed on every publish._