353 lines
8.0 KiB
Markdown
353 lines
8.0 KiB
Markdown
|
# meow
|
||
|
|
|
||
|
|
> CLI app helper
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
## Features
|
||
|
|
|
||
|
|
- Parses arguments
|
||
|
|
- Converts flags to [camelCase](https://github.com/sindresorhus/camelcase)
|
||
|
|
- Negates flags when using the `--no-` prefix
|
||
|
|
- Outputs version when `--version`
|
||
|
|
- Outputs description and supplied help text when `--help`
|
||
|
|
- Makes unhandled rejected promises [fail hard](https://github.com/sindresorhus/hard-rejection) instead of the default silent fail
|
||
|
|
- Sets the process title to the binary name defined in package.json
|
||
|
|
|
||
|
|
## Install
|
||
|
|
|
||
|
|
```
|
||
|
|
$ npm install meow
|
||
|
|
```
|
||
|
|
|
||
|
|
## Usage
|
||
|
|
|
||
|
|
```
|
||
|
|
$ ./foo-app.js unicorns --rainbow
|
||
|
|
```
|
||
|
|
|
||
|
|
**CommonJS**
|
||
|
|
|
||
|
|
```js
|
||
|
|
#!/usr/bin/env node
|
||
|
|
'use strict';
|
||
|
|
const meow = require('meow');
|
||
|
|
const foo = require('.');
|
||
|
|
|
||
|
|
const cli = meow(`
|
||
|
|
Usage
|
||
|
|
$ foo <input>
|
||
|
|
|
||
|
|
Options
|
||
|
|
--rainbow, -r Include a rainbow
|
||
|
|
|
||
|
|
Examples
|
||
|
|
$ foo unicorns --rainbow
|
||
|
|
🌈 unicorns 🌈
|
||
|
|
`, {
|
||
|
|
flags: {
|
||
|
|
rainbow: {
|
||
|
|
type: 'boolean',
|
||
|
|
alias: 'r'
|
||
|
|
}
|
||
|
|
}
|
||
|
|
});
|
||
|
|
/*
|
||
|
|
{
|
||
|
|
input: ['unicorns'],
|
||
|
|
flags: {rainbow: true},
|
||
|
|
...
|
||
|
|
}
|
||
|
|
*/
|
||
|
|
|
||
|
|
foo(cli.input[0], cli.flags);
|
||
|
|
```
|
||
|
|
|
||
|
|
**ES Modules**
|
||
|
|
|
||
|
|
```js
|
||
|
|
#!/usr/bin/env node
|
||
|
|
import {createRequire} from 'module';
|
||
|
|
import foo from './lib/index.js';
|
||
|
|
|
||
|
|
const meow = createRequire(import.meta.url)('meow');
|
||
|
|
|
||
|
|
const cli = meow(`
|
||
|
|
Usage
|
||
|
|
$ foo <input>
|
||
|
|
|
||
|
|
Options
|
||
|
|
--rainbow, -r Include a rainbow
|
||
|
|
|
||
|
|
Examples
|
||
|
|
$ foo unicorns --rainbow
|
||
|
|
🌈 unicorns 🌈
|
||
|
|
`, {
|
||
|
|
flags: {
|
||
|
|
rainbow: {
|
||
|
|
type: 'boolean',
|
||
|
|
alias: 'r'
|
||
|
|
}
|
||
|
|
}
|
||
|
|
});
|
||
|
|
/*
|
||
|
|
{
|
||
|
|
input: ['unicorns'],
|
||
|
|
flags: {rainbow: true},
|
||
|
|
...
|
||
|
|
}
|
||
|
|
*/
|
||
|
|
|
||
|
|
foo(cli.input[0], cli.flags);
|
||
|
|
```
|
||
|
|
|
||
|
|
## API
|
||
|
|
|
||
|
|
### meow(helpText, options?)
|
||
|
|
### meow(options)
|
||
|
|
|
||
|
|
Returns an `object` with:
|
||
|
|
|
||
|
|
- `input` *(Array)* - Non-flag arguments
|
||
|
|
- `flags` *(Object)* - Flags converted to camelCase excluding aliases
|
||
|
|
- `unnormalizedFlags` *(Object)* - Flags converted to camelCase including aliases
|
||
|
|
- `pkg` *(Object)* - The `package.json` object
|
||
|
|
- `help` *(string)* - The help text used with `--help`
|
||
|
|
- `showHelp([exitCode=2])` *(Function)* - Show the help text and exit with `exitCode`
|
||
|
|
- `showVersion()` *(Function)* - Show the version text and exit
|
||
|
|
|
||
|
|
#### helpText
|
||
|
|
|
||
|
|
Type: `string`
|
||
|
|
|
||
|
|
Shortcut for the `help` option.
|
||
|
|
|
||
|
|
#### options
|
||
|
|
|
||
|
|
Type: `object`
|
||
|
|
|
||
|
|
##### flags
|
||
|
|
|
||
|
|
Type: `object`
|
||
|
|
|
||
|
|
Define argument flags.
|
||
|
|
|
||
|
|
The key is the flag name in camel-case and the value is an object with any of:
|
||
|
|
|
||
|
|
- `type`: Type of value. (Possible values: `string` `boolean` `number`)
|
||
|
|
- `alias`: Usually used to define a short flag alias.
|
||
|
|
- `default`: Default value when the flag is not specified.
|
||
|
|
- `isRequired`: Determine if the flag is required. (Default: false)
|
||
|
|
- If it's only known at runtime whether the flag is required or not, you can pass a `Function` instead of a `boolean`, which based on the given flags and other non-flag arguments, should decide if the flag is required. Two arguments are passed to the function:
|
||
|
|
- The first argument is the **flags** object, which contains the flags converted to camel-case excluding aliases.
|
||
|
|
- The second argument is the **input** string array, which contains the non-flag arguments.
|
||
|
|
- The function should return a `boolean`, true if the flag is required, otherwise false.
|
||
|
|
- `isMultiple`: Indicates a flag can be set multiple times. Values are turned into an array. (Default: false)
|
||
|
|
- Multiple values are provided by specifying the flag multiple times, for example, `$ foo -u rainbow -u cat`. Space- or comma-separated values are [currently *not* supported](https://github.com/sindresorhus/meow/issues/164).
|
||
|
|
|
||
|
|
Note that flags are always defined using a camel-case key (`myKey`), but will match arguments in kebab-case (`--my-key`).
|
||
|
|
|
||
|
|
Example:
|
||
|
|
|
||
|
|
```js
|
||
|
|
flags: {
|
||
|
|
unicorn: {
|
||
|
|
type: 'string',
|
||
|
|
alias: 'u',
|
||
|
|
default: ['rainbow', 'cat'],
|
||
|
|
isMultiple: true,
|
||
|
|
isRequired: (flags, input) => {
|
||
|
|
if (flags.otherFlag) {
|
||
|
|
return true;
|
||
|
|
}
|
||
|
|
|
||
|
|
return false;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
```
|
||
|
|
|
||
|
|
##### description
|
||
|
|
|
||
|
|
Type: `string | boolean`\
|
||
|
|
Default: The package.json `"description"` property
|
||
|
|
|
||
|
|
Description to show above the help text.
|
||
|
|
|
||
|
|
Set it to `false` to disable it altogether.
|
||
|
|
|
||
|
|
##### help
|
||
|
|
|
||
|
|
Type: `string | boolean`
|
||
|
|
|
||
|
|
The help text you want shown.
|
||
|
|
|
||
|
|
The input is reindented and starting/ending newlines are trimmed which means you can use a [template literal](https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/template_strings) without having to care about using the correct amount of indent.
|
||
|
|
|
||
|
|
The description will be shown above your help text automatically.
|
||
|
|
|
||
|
|
##### version
|
||
|
|
|
||
|
|
Type: `string | boolean`\
|
||
|
|
Default: The package.json `"version"` property
|
||
|
|
|
||
|
|
Set a custom version output.
|
||
|
|
|
||
|
|
##### autoHelp
|
||
|
|
|
||
|
|
Type: `boolean`\
|
||
|
|
Default: `true`
|
||
|
|
|
||
|
|
Automatically show the help text when the `--help` flag is present. Useful to set this value to `false` when a CLI manages child CLIs with their own help text.
|
||
|
|
|
||
|
|
This option is only considered when there is only one argument in `process.argv`.
|
||
|
|
|
||
|
|
##### autoVersion
|
||
|
|
|
||
|
|
Type: `boolean`\
|
||
|
|
Default: `true`
|
||
|
|
|
||
|
|
Automatically show the version text when the `--version` flag is present. Useful to set this value to `false` when a CLI manages child CLIs with their own version text.
|
||
|
|
|
||
|
|
This option is only considered when there is only one argument in `process.argv`.
|
||
|
|
|
||
|
|
##### pkg
|
||
|
|
|
||
|
|
Type: `object`\
|
||
|
|
Default: Closest package.json upwards
|
||
|
|
|
||
|
|
package.json as an `object`.
|
||
|
|
|
||
|
|
*You most likely don't need this option.*
|
||
|
|
|
||
|
|
##### argv
|
||
|
|
|
||
|
|
Type: `string[]`\
|
||
|
|
Default: `process.argv.slice(2)`
|
||
|
|
|
||
|
|
Custom arguments object.
|
||
|
|
|
||
|
|
##### inferType
|
||
|
|
|
||
|
|
Type: `boolean`\
|
||
|
|
Default: `false`
|
||
|
|
|
||
|
|
Infer the argument type.
|
||
|
|
|
||
|
|
By default, the argument `5` in `$ foo 5` becomes a string. Enabling this would infer it as a number.
|
||
|
|
|
||
|
|
##### booleanDefault
|
||
|
|
|
||
|
|
Type: `boolean | null | undefined`\
|
||
|
|
Default: `false`
|
||
|
|
|
||
|
|
Value of `boolean` flags not defined in `argv`.
|
||
|
|
|
||
|
|
If set to `undefined`, the flags not defined in `argv` will be excluded from the result.
|
||
|
|
The `default` value set in `boolean` flags take precedence over `booleanDefault`.
|
||
|
|
|
||
|
|
_Note: If used in conjunction with `isMultiple`, the default flag value is set to `[]`._
|
||
|
|
|
||
|
|
__Caution: Explicitly specifying `undefined` for `booleanDefault` has different meaning from omitting key itself.__
|
||
|
|
|
||
|
|
Example:
|
||
|
|
|
||
|
|
```js
|
||
|
|
const meow = require('meow');
|
||
|
|
|
||
|
|
const cli = meow(`
|
||
|
|
Usage
|
||
|
|
$ foo
|
||
|
|
|
||
|
|
Options
|
||
|
|
--rainbow, -r Include a rainbow
|
||
|
|
--unicorn, -u Include a unicorn
|
||
|
|
--no-sparkles Exclude sparkles
|
||
|
|
|
||
|
|
Examples
|
||
|
|
$ foo
|
||
|
|
🌈 unicorns✨🌈
|
||
|
|
`, {
|
||
|
|
booleanDefault: undefined,
|
||
|
|
flags: {
|
||
|
|
rainbow: {
|
||
|
|
type: 'boolean',
|
||
|
|
default: true,
|
||
|
|
alias: 'r'
|
||
|
|
},
|
||
|
|
unicorn: {
|
||
|
|
type: 'boolean',
|
||
|
|
default: false,
|
||
|
|
alias: 'u'
|
||
|
|
},
|
||
|
|
cake: {
|
||
|
|
type: 'boolean',
|
||
|
|
alias: 'c'
|
||
|
|
},
|
||
|
|
sparkles: {
|
||
|
|
type: 'boolean',
|
||
|
|
default: true
|
||
|
|
}
|
||
|
|
}
|
||
|
|
});
|
||
|
|
/*
|
||
|
|
{
|
||
|
|
flags: {
|
||
|
|
rainbow: true,
|
||
|
|
unicorn: false,
|
||
|
|
sparkles: true
|
||
|
|
},
|
||
|
|
unnormalizedFlags: {
|
||
|
|
rainbow: true,
|
||
|
|
r: true,
|
||
|
|
unicorn: false,
|
||
|
|
u: false,
|
||
|
|
sparkles: true
|
||
|
|
},
|
||
|
|
…
|
||
|
|
}
|
||
|
|
*/
|
||
|
|
```
|
||
|
|
|
||
|
|
##### hardRejection
|
||
|
|
|
||
|
|
Type: `boolean`\
|
||
|
|
Default: `true`
|
||
|
|
|
||
|
|
Whether to use [`hard-rejection`](https://github.com/sindresorhus/hard-rejection) or not. Disabling this can be useful if you need to handle `process.on('unhandledRejection')` yourself.
|
||
|
|
|
||
|
|
#### allowUnknownFlags
|
||
|
|
|
||
|
|
Type `boolean`\
|
||
|
|
Default: `true`
|
||
|
|
|
||
|
|
Whether to allow unknown flags or not.
|
||
|
|
|
||
|
|
## Promises
|
||
|
|
|
||
|
|
Meow will make unhandled rejected promises [fail hard](https://github.com/sindresorhus/hard-rejection) instead of the default silent fail. Meaning you don't have to manually `.catch()` promises used in your CLI.
|
||
|
|
|
||
|
|
## Tips
|
||
|
|
|
||
|
|
See [`chalk`](https://github.com/chalk/chalk) if you want to colorize the terminal output.
|
||
|
|
|
||
|
|
See [`get-stdin`](https://github.com/sindresorhus/get-stdin) if you want to accept input from stdin.
|
||
|
|
|
||
|
|
See [`conf`](https://github.com/sindresorhus/conf) if you need to persist some data.
|
||
|
|
|
||
|
|
See [`update-notifier`](https://github.com/yeoman/update-notifier) if you want update notifications.
|
||
|
|
|
||
|
|
[More useful CLI utilities…](https://github.com/sindresorhus/awesome-nodejs#command-line-utilities)
|
||
|
|
|
||
|
|
---
|
||
|
|
|
||
|
|
<div align="center">
|
||
|
|
<b>
|
||
|
|
<a href="https://tidelift.com/subscription/pkg/npm-meow?utm_source=npm-meow&utm_medium=referral&utm_campaign=readme">Get professional support for this package with a Tidelift subscription</a>
|
||
|
|
</b>
|
||
|
|
<br>
|
||
|
|
<sub>
|
||
|
|
Tidelift helps make open source sustainable for maintainers while giving companies<br>assurances about security, maintenance, and licensing for their dependencies.
|
||
|
|
</sub>
|
||
|
|
</div>
|