252 lines
7.2 KiB
Markdown
252 lines
7.2 KiB
Markdown
# obug
|
|
|
|
[![npm version][npm-version-src]][npm-version-href]
|
|
[![npm downloads][npm-downloads-src]][npm-downloads-href]
|
|
[![JSR][jsr-badge-src]][jsr-badge-href]
|
|
[![Unit Test][unit-test-src]][unit-test-href]
|
|
|
|
A lightweight JavaScript debugging utility, forked from [debug](https://www.npmjs.com/package/debug), featuring TypeScript and ESM support.
|
|
|
|
> [!NOTE]
|
|
> obug v1 retains most of the compatibility with [debug](https://github.com/debug-js/debug), but drops support for older browsers and Node.js, making it a drop-in replacement.
|
|
>
|
|
> obug v2 refactors some API imports and usage for better support of ESM and TypeScript, easier customization, and an even smaller package size.
|
|
|
|
## Key Differences from `debug`
|
|
|
|
- ✨ Minimal footprint
|
|
- 7.7 kB package size
|
|
- 1.4 KB minified + gzipped for browsers
|
|
- 📦 Zero dependencies
|
|
- 📝 Full TypeScript support
|
|
- 🚀 Native ESM compatibility
|
|
- 🌐 Optimized for modern runtimes
|
|
- ES2015+ browsers
|
|
- Modern Node.js versions
|
|
- 🎨 Customizable formatting
|
|
|
|
## Installation
|
|
|
|
```bash
|
|
npm install obug
|
|
```
|
|
|
|
## Usage
|
|
|
|
```ts
|
|
import { createDebug, disable, enable, enabled, namespaces } from 'obug'
|
|
|
|
// Get the currently enabled namespaces
|
|
console.log(namespaces())
|
|
|
|
const debug = createDebug('my-namespace', {
|
|
// All options are optional
|
|
|
|
useColors: true, // false, true, undefined for auto-detect
|
|
color: 2, // custom color
|
|
// custom formatArgs
|
|
formatArgs(args) {},
|
|
formatters: {},
|
|
// Node.js only
|
|
inspectOpts: {},
|
|
|
|
// custom log
|
|
log: console.log,
|
|
})
|
|
|
|
debug('This is a debug message')
|
|
console.log(
|
|
debug.namespace, // 'my-namespace'
|
|
debug.enabled, // Check if enabled
|
|
debug.useColors, // true
|
|
debug.color, // 2
|
|
debug.formatArgs, // custom formatArgs
|
|
debug.formatters, // {}
|
|
debug.inspectOpts, // {}
|
|
debug.log, // implemented log function
|
|
)
|
|
|
|
// Create a sub-namespace, and it will inherit options from the parent debugger
|
|
const sub = debug.extend('sub-namespace')
|
|
sub('This is a sub-namespace debug message')
|
|
console.log(sub.namespace) // 'my-namespace:sub-namespace'
|
|
```
|
|
|
|
## How to use
|
|
|
|
### Enabling debug output
|
|
|
|
obug picks up enabled namespaces from the `DEBUG` environment variable in Node.js, or from `localStorage.debug` in browsers.
|
|
|
|
In Node.js:
|
|
|
|
```bash
|
|
DEBUG=app:* node app.js
|
|
```
|
|
|
|
On Windows (CMD):
|
|
|
|
```cmd
|
|
set DEBUG=app:* & node app.js
|
|
```
|
|
|
|
On Windows (PowerShell):
|
|
|
|
```powershell
|
|
$env:DEBUG='app:*'; node app.js
|
|
```
|
|
|
|
In the browser, set the value in DevTools and refresh the page:
|
|
|
|
```js
|
|
localStorage.debug = 'app:*'
|
|
```
|
|
|
|
### Wildcards and exclusion
|
|
|
|
The `*` character is a wildcard. Suppose your library has debuggers named `connect:bodyParser`, `connect:compress`, and `connect:session` — instead of listing each one, use `DEBUG=connect:*`. Use `DEBUG=*` to enable everything.
|
|
|
|
Exclude namespaces by prefixing them with `-`:
|
|
|
|
```bash
|
|
DEBUG=*,-connect:* node app.js
|
|
```
|
|
|
|
### Namespace conventions
|
|
|
|
If you're using obug in a library, prefix your namespaces with the library name and use `:` to separate features (e.g. `connect:bodyParser`). This lets users opt into the parts they care about without guessing names.
|
|
|
|
### Extending a namespace
|
|
|
|
Use `.extend()` to create a sub-namespace that inherits options from its parent:
|
|
|
|
```ts
|
|
const log = createDebug('auth')
|
|
const logSign = log.extend('sign') // 'auth:sign'
|
|
const logLogin = log.extend('login') // 'auth:login'
|
|
|
|
log('hello') // auth hello
|
|
logSign('hello') // auth:sign hello
|
|
logLogin('hello') // auth:login hello
|
|
```
|
|
|
|
### Formatters
|
|
|
|
obug uses [printf-style](https://wikipedia.org/wiki/Printf_format_string) formatting. Built-in formatters:
|
|
|
|
| Formatter | Representation |
|
|
| --------- | -------------------------------------------------- |
|
|
| `%O` | Pretty-print an Object on multiple lines. |
|
|
| `%o` | Pretty-print an Object all on a single line. |
|
|
| `%%` | Single percent sign. Does not consume an argument. |
|
|
|
|
Other format specifiers supported by Node's `util.format` (`%s`, `%d`, `%j`, …) and the browser console pass through to the underlying logger.
|
|
|
|
#### Custom formatters
|
|
|
|
Register custom formatters via the `formatters` option. For example, to render a `Buffer` as hex with `%h`:
|
|
|
|
```ts
|
|
const debug = createDebug('foo', {
|
|
formatters: {
|
|
h: (v) => v.toString('hex'),
|
|
},
|
|
})
|
|
|
|
debug('this is hex: %h', Buffer.from('hello world'))
|
|
// foo this is hex: 68656c6c6f20776f726c64 +0ms
|
|
```
|
|
|
|
### Dynamic enable / disable
|
|
|
|
You can toggle namespaces at runtime:
|
|
|
|
```ts
|
|
import { disable, enable, enabled, namespaces } from 'obug'
|
|
|
|
enable('app:*')
|
|
console.log(enabled('app:server')) // true
|
|
|
|
const previous = disable()
|
|
console.log(enabled('app:server')) // false
|
|
|
|
// Restore later
|
|
enable(previous)
|
|
```
|
|
|
|
`namespaces()` returns the string of currently enabled namespaces. Note that calling `enable()` overrides the value initially read from `DEBUG`.
|
|
|
|
### Checking whether a debugger is enabled
|
|
|
|
Guard expensive work behind the `enabled` property:
|
|
|
|
```ts
|
|
const debug = createDebug('http')
|
|
|
|
if (debug.enabled) {
|
|
// expensive computation only when enabled
|
|
}
|
|
```
|
|
|
|
You can also force the state by assigning to `debug.enabled` directly.
|
|
|
|
### Custom output
|
|
|
|
By default, obug writes to `stderr` in Node.js and to the console in browsers. Override the `log` option to redirect output per-namespace:
|
|
|
|
```ts
|
|
const log = createDebug('app:log', {
|
|
log: console.log,
|
|
})
|
|
|
|
const error = createDebug('app:error') // still goes to stderr
|
|
```
|
|
|
|
### Environment variables (Node.js)
|
|
|
|
| Name | Purpose |
|
|
| ------------------- | ----------------------------------------------- |
|
|
| `DEBUG` | Enables/disables specific debugging namespaces. |
|
|
| `DEBUG_HIDE_DATE` | Hide date from debug output (non-TTY). |
|
|
| `DEBUG_COLORS` | Whether to use colors in the debug output. |
|
|
| `DEBUG_DEPTH` | Object inspection depth. |
|
|
| `DEBUG_SHOW_HIDDEN` | Shows hidden properties on inspected objects. |
|
|
|
|
Variables prefixed with `DEBUG_` are converted to camelCase keys on the options object passed to Node's [`util.inspect()`](https://nodejs.org/api/util.html#util_util_inspect_object_options) for the `%o` / `%O` formatters.
|
|
|
|
## Original Authors
|
|
|
|
As obug is a fork of debug with significant modifications, we would like to acknowledge the original authors:
|
|
|
|
- TJ Holowaychuk
|
|
- Nathan Rajlich
|
|
- Andrew Rhyne
|
|
- Josh Junon
|
|
|
|
## Sponsors
|
|
|
|
<p align="center">
|
|
<a href="https://cdn.jsdelivr.net/gh/sxzz/sponsors/sponsors.svg">
|
|
<img src='https://cdn.jsdelivr.net/gh/sxzz/sponsors/sponsors.svg'/>
|
|
</a>
|
|
</p>
|
|
|
|
## License
|
|
|
|
[MIT](./LICENSE) License © 2025-PRESENT [Kevin Deng](https://github.com/sxzz)
|
|
|
|
[The MIT License](./LICENSE) Copyright (c) 2014-2017 TJ Holowaychuk <tj@vision-media.ca>
|
|
|
|
[The MIT License](./LICENSE) Copyright (c) 2018-2021 Josh Junon
|
|
|
|
<!-- Badges -->
|
|
|
|
[npm-version-src]: https://img.shields.io/npm/v/obug.svg
|
|
[npm-version-href]: https://npmjs.com/package/obug
|
|
[npm-downloads-src]: https://img.shields.io/npm/dm/obug
|
|
[npm-downloads-href]: https://www.npmcharts.com/compare/obug?interval=30
|
|
[unit-test-src]: https://github.com/sxzz/obug/actions/workflows/unit-test.yml/badge.svg
|
|
[unit-test-href]: https://github.com/sxzz/obug/actions/workflows/unit-test.yml
|
|
[jsr-badge-src]: https://jsr.io/badges/@sxzz/obug
|
|
[jsr-badge-href]: https://jsr.io/@sxzz/obug
|