@stackline/fault

Functional errors with formatted output.

Documentation | npm | Issues | Repository

Current package version: 1.0.2

Why this package?

@stackline/fault is the Stackline-maintained distribution of fault@2.0.1. It is an independent continuation of fault; original authors and licenses remain credited below.

Compatibility

Installation

npm install @stackline/fault

Preserve existing imports and plugin resolution with an npm alias:

npm install fault@npm:@stackline/fault

Usage and API reference

fault

Functional errors with formatted output.

Contents

• What is this?
• When should I use this?
• Install
• Use
• API
  • fault(format?[, values…])
• Types
• Compatibility
• Security
• Related
• Contribute
• License

What is this?

This package adds printf-like interpolation to errors.

When should I use this?

This package useful when you frequently display parameters in error messages and manual string concatenation is becoming verbose.

Install

This package is ESM only. In Node.js (version 12.20+, 14.14+, or 16.0+), install with npm:

npm install @stackline/fault

In Deno with Skypack:

import {fault} from 'https://cdn.skypack.dev/fault@2?dts'

In browsers with Skypack:

<script type="module">
  import {fault} from 'https://cdn.skypack.dev/fault@2?min'
</script>

Use

import {fault} from '@stackline/fault'

throw fault('Hello %s!', 'Eric')

Yields:

Error: Hello Eric!
    at FormattedError (~/node_modules/fault/index.js:30:12)
    at Object.<anonymous> (~/example.js:3:7)
    …

Or, format a float in a type error:

import {fault} from '@stackline/fault'

throw fault.type('Who doesn’t like %f? 🍰', Math.PI)

Yields:

TypeError: Who doesn’t like 3.141593? 🍰
    at Function.FormattedError [as type] (~/node_modules/fault/index.js:30:12)
    at Object.<anonymous> (~/example.js:3:7)

API

This package exports the following identifiers: fault and create. There is no default export.

fault(format?[, values…])

Create an error with a printf-like formatted message.

Parameters

• format (string, optional) — template string
• values (*, optional) — values to render in format

Returns

An Error instance.

Formatters

The following formatters are supported in format:

• %s — string
• %b — binary
• %c — character
• %d — decimal
• %f — floating point
• %o — octal
• %x — lowercase hexadecimal
• %X — uppercase hexadecimal
• % followed by any other character, prints that character

See samsonjs/format for argument parsing.

Other errors

• fault.eval(format?[, values…]) — EvalError
• fault.range(format?[, values…]) — RangeError
• fault.reference(format?[, values…]) — ReferenceError
• fault.syntax(format?[, values…]) — SyntaxError
• fault.type(format?[, values…]) — TypeError
• fault.uri(format?[, values…]) — URIError

create(Constructor)

Factory to create instances of ErrorConstructor with support for formatting. Used internally to wrap the global error constructors and exposed for custom errors. Returns a function just like fault.

Types

This package is fully typed with TypeScript. There are no extra exported types.

Compatibility

This package is at least compatible with all maintained versions of Node.js. As of now, that is Node.js 12.20+, 14.14+, and 16.0+. It also works in Deno and modern browsers.

Security

This package is safe.

Related

• wooorm/bail — throw if given an error

Contribute

Yes please! See How to Contribute to Open Source.

License

MIT © Titus Wormer

Credits and original authors

• Original project: fault.
• Titus Wormer.
• Copyright (c) 2015 Titus Wormer tituswormer@gmail.com.
• Stackline maintenance: Alexandro Paixao Marques and Stackline contributors.

Original copyright, license notices and contributor acknowledgements remain part of this distribution. Stackline maintenance does not replace authorship of the original work.

Community and Links

• Stackline website
• GitHub projects
• npm packages
• Reddit community — r/Stackline
• Maintainer LinkedIn

Use this repository's issue tracker for reproducible bugs and feature requests. Join r/Stackline for examples, usage questions and release discussions.