https://github.com/octet-stream/invariant

Declarative errors throwing for Node.js
https://github.com/octet-stream/invariant

error-handling error-throwing format invariant javascript javascript-library nodejs sprintf

Last synced: 9 months ago
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Declarative errors throwing for Node.js

• Host: GitHub
• URL: https://github.com/octet-stream/invariant
• Owner: octet-stream
• License: mit
• Created: 2017-07-28T14:08:30.000Z (over 8 years ago)
• Default Branch: master
• Last Pushed: 2023-02-10T03:28:14.000Z (about 3 years ago)
• Last Synced: 2025-04-19T09:08:15.842Z (10 months ago)
• Topics: error-handling, error-throwing, format, invariant, javascript, javascript-library, nodejs, sprintf
• Language: JavaScript
• Homepage: https://www.npmjs.com/package/@octetstream/invariant
• Size: 501 KB
• Stars: 0
• Watchers: 0
• Forks: 0
• Open Issues: 5
• Metadata Files:
  • Readme: readme.md
  • License: license

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README

          
# @octetstream/invariant

Declarative errors throwing for Node.js

[![dependencies Status](https://david-dm.org/octet-stream/invariant/status.svg)](https://david-dm.org/octet-stream/invariant)

[![devDependencies Status](https://david-dm.org/octet-stream/invariant/dev-status.svg)](https://david-dm.org/octet-stream/invariant?type=dev)

[![Build Status](https://travis-ci.org/octet-stream/invariant.svg?branch=master)](https://travis-ci.org/octet-stream/invariant)

[![Code Coverage](https://codecov.io/github/octet-stream/invariant/coverage.svg?branch=master)](https://codecov.io/github/octet-stream/invariant?branch=master)

## API

### `invariant(predicate, error) -> {void}`

  - **boolean** predicate – a result of some condition. Error will threw if predicate is `true`.

  - **object** error – some error object

### `invatiant(predicate, message[, ...format]) -> {void}`

  - **boolean** predicate – a result of some condition. Error will threw if predicate is `true`.

  - **string** message – an error message

  - **any** format – see more about the format in a [sprintf-js documentation](https://github.com/alexei/sprintf.js)

### `invariant(predicate, Error, message[, ...format]) -> {void}`

  - **boolean** predicate – a result of some condition. Error will threw if predicate is `true`.

  - **Function** Error – custom error class that will be used as an error constructor

  - **string** message – an error message

  - **any** format – see more about the format in a [sprintf-js documentation](https://github.com/alexei/sprintf.js)

### `invariant.reject(predicate, message[, ...format]) -> {Promise}`

  Do the same things as `invariant`, but returns Promise that will be rejected when predicate is true.

  This function have same API as `invariant`.

## Example

```js

  import invariant from "@octetstream/invariant"

  // some of your code...

  // Will threw a TypeError if "value" is not a string

  invariant(typeof value !== "string", TypeError, "The value should be a string, but given type is: %s", typeof value)

  invariant(typeof value !== "string", "The value should be a string, but given type is: %s", typeof value)

  invariant(typeof value !== "string", new TypeError(`The value should be a string, but given type is: ${typeof value}`))

  // Will return rejected Promise instead of throw error synchronously

  invariant.reject(typeof value !== "string", TypeError, "The value should be a string, but given type is: %s", typeof value)

    .catch(err => console.error(err))

```