https://github.com/andrejewski/throw-return

Return using throw
https://github.com/andrejewski/throw-return

Last synced: 6 months ago
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Return using throw

• Host: GitHub
• URL: https://github.com/andrejewski/throw-return
• Owner: andrejewski
• License: mit
• Created: 2018-10-28T17:03:54.000Z (about 7 years ago)
• Default Branch: master
• Last Pushed: 2020-05-11T17:16:34.000Z (over 5 years ago)
• Last Synced: 2025-06-16T17:52:08.486Z (7 months ago)
• Language: JavaScript
• Homepage:
• Size: 39.1 KB
• Stars: 3
• Watchers: 2
• Forks: 0
• Open Issues: 3
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

          
# throw-return

> Return using throw

```sh

npm install throw-return

```

[![npm](https://img.shields.io/npm/v/throw-return.svg)](https://www.npmjs.com/package/throw-return)

[![Build Status](https://travis-ci.org/andrejewski/throw-return.svg?branch=master)](https://travis-ci.org/andrejewski/throw-return)

[![Greenkeeper badge](https://badges.greenkeeper.io/andrejewski/throw-return.svg)](https://greenkeeper.io/)

Throw errors to communicate a return value.

**Warning:**

Evaluate your use cases before using this library.

Using error handling to short-circuit functions is slower and more obscure than returning.

This library should be used as part of a larger abstraction.

Unless that abstraction provides more benefits in itself, go with plain `return`.

## Documentation

- [`throwReturnError(value[, message])`](#throwreturnerror)

- [`handleReturnError(func)`](#handlereturnerror)

### `throwReturnError`

> `throwReturnError(value: any[, message: String])`

Throw an error communicating `value` as the return value.

Optionally give the error a `message`.

### `handleReturnError`

> `handleReturnError(func: Function): any`

Invoke `func` and, if a `throw-return` error is thrown, return the communicated value.

If a promise is returned rejecting a `throw-error` error, the communicated value is resolved.

## Example

We have found `if (!y) return x` too tiresome to write.

Let's build an `assert(y, x)` to save some keystrokes.

Instead of this:

```js

function example () {

  if (!condition1) {

    return value1

  }

  if (!condition2) {

    return value2

  }

  return value3

}

```

We can do:

```js

function example () {

  assert(condition1, value1)

  assert(condition2, value2)

  return value3

}

```

If you define `assert` and control all calls to `example`:

```js

function assert (condition, value) {

  if (!condition) {

    throwReturnError(value)

  }

}

function run (func) {

  return handleReturnError(func)

}

const value = run(example)

```