|
|
# yargs-parser
[](https://www.npmjs.com/package/yargs-parser)[](https://conventionalcommits.org)
The mighty option parser used by [yargs](https://github.com/yargs/yargs).
visit the [yargs website](http://yargs.js.org/) for more examples, and thorough usage instructions.
<img width="250" src="https://raw.githubusercontent.com/yargs/yargs-parser/main/yargs-logo.png">
## Example
```shnpm i yargs-parser --save```
```jsconst argv = require('yargs-parser')(process.argv.slice(2))console.log(argv)```
```console$ node example.js --foo=33 --bar hello{ _: [], foo: 33, bar: 'hello' }```
_or parse a string!_
```jsconst argv = require('yargs-parser')('--foo=99 --bar=33')console.log(argv)```
```console{ _: [], foo: 99, bar: 33 }```
Convert an array of mixed types before passing to `yargs-parser`:
```jsconst parse = require('yargs-parser')parse(['-f', 11, '--zoom', 55].join(' ')) // <-- array to stringparse(['-f', 11, '--zoom', 55].map(String)) // <-- array of strings```
## Deno Example
As of `v19` `yargs-parser` supports [Deno](https://github.com/denoland/deno):
```typescriptimport parser from "https://deno.land/x/yargs_parser/deno.ts";
const argv = parser('--foo=99 --bar=9987930', { string: ['bar']})console.log(argv)```
## ESM Example
As of `v19` `yargs-parser` supports ESM (_both in Node.js and in the browser_):
**Node.js:**
```jsimport parser from 'yargs-parser'
const argv = parser('--foo=99 --bar=9987930', { string: ['bar']})console.log(argv)```
**Browsers:**
```html<!doctype html><body> <script type="module"> import parser from "https://unpkg.com/yargs-parser@19.0.0/browser.js";
const argv = parser('--foo=99 --bar=9987930', { string: ['bar'] }) console.log(argv) </script></body>```
## API
### parser(args, opts={})
Parses command line arguments returning a simple mapping of keys and values.
**expects:**
* `args`: a string or array of strings representing the options to parse.* `opts`: provide a set of hints indicating how `args` should be parsed: * `opts.alias`: an object representing the set of aliases for a key: `{alias: {foo: ['f']}}`. * `opts.array`: indicate that keys should be parsed as an array: `{array: ['foo', 'bar']}`.<br> Indicate that keys should be parsed as an array and coerced to booleans / numbers:<br> `{array: [{ key: 'foo', boolean: true }, {key: 'bar', number: true}]}`. * `opts.boolean`: arguments should be parsed as booleans: `{boolean: ['x', 'y']}`. * `opts.coerce`: provide a custom synchronous function that returns a coerced value from the argument provided (or throws an error). For arrays the function is called only once for the entire array:<br> `{coerce: {foo: function (arg) {return modifiedArg}}}`. * `opts.config`: indicate a key that represents a path to a configuration file (this file will be loaded and parsed). * `opts.configObjects`: configuration objects to parse, their properties will be set as arguments:<br> `{configObjects: [{'x': 5, 'y': 33}, {'z': 44}]}`. * `opts.configuration`: provide configuration options to the yargs-parser (see: [configuration](#configuration)). * `opts.count`: indicate a key that should be used as a counter, e.g., `-vvv` = `{v: 3}`. * `opts.default`: provide default values for keys: `{default: {x: 33, y: 'hello world!'}}`. * `opts.envPrefix`: environment variables (`process.env`) with the prefix provided should be parsed. * `opts.narg`: specify that a key requires `n` arguments: `{narg: {x: 2}}`. * `opts.normalize`: `path.normalize()` will be applied to values set to this key. * `opts.number`: keys should be treated as numbers. * `opts.string`: keys should be treated as strings (even if they resemble a number `-x 33`).
**returns:**
* `obj`: an object representing the parsed value of `args` * `key/value`: key value pairs for each argument and their aliases. * `_`: an array representing the positional arguments. * [optional] `--`: an array with arguments after the end-of-options flag `--`.
### require('yargs-parser').detailed(args, opts={})
Parses a command line string, returning detailed information required by theyargs engine.
**expects:**
* `args`: a string or array of strings representing options to parse.* `opts`: provide a set of hints indicating how `args`, inputs are identical to `require('yargs-parser')(args, opts={})`.
**returns:**
* `argv`: an object representing the parsed value of `args` * `key/value`: key value pairs for each argument and their aliases. * `_`: an array representing the positional arguments. * [optional] `--`: an array with arguments after the end-of-options flag `--`.* `error`: populated with an error object if an exception occurred during parsing.* `aliases`: the inferred list of aliases built by combining lists in `opts.alias`.* `newAliases`: any new aliases added via camel-case expansion: * `boolean`: `{ fooBar: true }`* `defaulted`: any new argument created by `opts.default`, no aliases included. * `boolean`: `{ foo: true }`* `configuration`: given by default settings and `opts.configuration`.
<a name="configuration"></a>
### Configuration
The yargs-parser applies several automated transformations on the keys providedin `args`. These features can be turned on and off using the `configuration` fieldof `opts`.
```jsvar parsed = parser(['--no-dice'], { configuration: { 'boolean-negation': false }})```
### short option groups
* default: `true`.* key: `short-option-groups`.
Should a group of short-options be treated as boolean flags?
```console$ node example.js -abc{ _: [], a: true, b: true, c: true }```
_if disabled:_
```console$ node example.js -abc{ _: [], abc: true }```
### camel-case expansion
* default: `true`.* key: `camel-case-expansion`.
Should hyphenated arguments be expanded into camel-case aliases?
```console$ node example.js --foo-bar{ _: [], 'foo-bar': true, fooBar: true }```
_if disabled:_
```console$ node example.js --foo-bar{ _: [], 'foo-bar': true }```
### dot-notation
* default: `true`* key: `dot-notation`
Should keys that contain `.` be treated as objects?
```console$ node example.js --foo.bar{ _: [], foo: { bar: true } }```
_if disabled:_
```console$ node example.js --foo.bar{ _: [], "foo.bar": true }```
### parse numbers
* default: `true`* key: `parse-numbers`
Should keys that look like numbers be treated as such?
```console$ node example.js --foo=99.3{ _: [], foo: 99.3 }```
_if disabled:_
```console$ node example.js --foo=99.3{ _: [], foo: "99.3" }```
### parse positional numbers
* default: `true`* key: `parse-positional-numbers`
Should positional keys that look like numbers be treated as such.
```console$ node example.js 99.3{ _: [99.3] }```
_if disabled:_
```console$ node example.js 99.3{ _: ['99.3'] }```
### boolean negation
* default: `true`* key: `boolean-negation`
Should variables prefixed with `--no` be treated as negations?
```console$ node example.js --no-foo{ _: [], foo: false }```
_if disabled:_
```console$ node example.js --no-foo{ _: [], "no-foo": true }```
### combine arrays
* default: `false`* key: `combine-arrays`
Should arrays be combined when provided by both command line arguments anda configuration file.
### duplicate arguments array
* default: `true`* key: `duplicate-arguments-array`
Should arguments be coerced into an array when duplicated:
```console$ node example.js -x 1 -x 2{ _: [], x: [1, 2] }```
_if disabled:_
```console$ node example.js -x 1 -x 2{ _: [], x: 2 }```
### flatten duplicate arrays
* default: `true`* key: `flatten-duplicate-arrays`
Should array arguments be coerced into a single array when duplicated:
```console$ node example.js -x 1 2 -x 3 4{ _: [], x: [1, 2, 3, 4] }```
_if disabled:_
```console$ node example.js -x 1 2 -x 3 4{ _: [], x: [[1, 2], [3, 4]] }```
### greedy arrays
* default: `true`* key: `greedy-arrays`
Should arrays consume more than one positional argument following their flag.
```console$ node example --arr 1 2{ _: [], arr: [1, 2] }```
_if disabled:_
```console$ node example --arr 1 2{ _: [2], arr: [1] }```
**Note: in `v18.0.0` we are considering defaulting greedy arrays to `false`.**
### nargs eats options
* default: `false`* key: `nargs-eats-options`
Should nargs consume dash options as well as positional arguments.
### negation prefix
* default: `no-`* key: `negation-prefix`
The prefix to use for negated boolean variables.
```console$ node example.js --no-foo{ _: [], foo: false }```
_if set to `quux`:_
```console$ node example.js --quuxfoo{ _: [], foo: false }```
### populate --
* default: `false`.* key: `populate--`
Should unparsed flags be stored in `--` or `_`.
_If disabled:_
```console$ node example.js a -b -- x y{ _: [ 'a', 'x', 'y' ], b: true }```
_If enabled:_
```console$ node example.js a -b -- x y{ _: [ 'a' ], '--': [ 'x', 'y' ], b: true }```
### set placeholder key
* default: `false`.* key: `set-placeholder-key`.
Should a placeholder be added for keys not set via the corresponding CLI argument?
_If disabled:_
```console$ node example.js -a 1 -c 2{ _: [], a: 1, c: 2 }```
_If enabled:_
```console$ node example.js -a 1 -c 2{ _: [], a: 1, b: undefined, c: 2 }```
### halt at non-option
* default: `false`.* key: `halt-at-non-option`.
Should parsing stop at the first positional argument? This is similar to how e.g. `ssh` parses its command line.
_If disabled:_
```console$ node example.js -a run b -x y{ _: [ 'b' ], a: 'run', x: 'y' }```
_If enabled:_
```console$ node example.js -a run b -x y{ _: [ 'b', '-x', 'y' ], a: 'run' }```
### strip aliased
* default: `false`* key: `strip-aliased`
Should aliases be removed before returning results?
_If disabled:_
```console$ node example.js --test-field 1{ _: [], 'test-field': 1, testField: 1, 'test-alias': 1, testAlias: 1 }```
_If enabled:_
```console$ node example.js --test-field 1{ _: [], 'test-field': 1, testField: 1 }```
### strip dashed
* default: `false`* key: `strip-dashed`
Should dashed keys be removed before returning results? This option has no effect if`camel-case-expansion` is disabled.
_If disabled:_
```console$ node example.js --test-field 1{ _: [], 'test-field': 1, testField: 1 }```
_If enabled:_
```console$ node example.js --test-field 1{ _: [], testField: 1 }```
### unknown options as args
* default: `false`* key: `unknown-options-as-args`
Should unknown options be treated like regular arguments? An unknown option is one that is notconfigured in `opts`.
_If disabled_
```console$ node example.js --unknown-option --known-option 2 --string-option --unknown-option2{ _: [], unknownOption: true, knownOption: 2, stringOption: '', unknownOption2: true }```
_If enabled_
```console$ node example.js --unknown-option --known-option 2 --string-option --unknown-option2{ _: ['--unknown-option'], knownOption: 2, stringOption: '--unknown-option2' }```
## Supported Node.js Versions
Libraries in this ecosystem make a best effort to track[Node.js' release schedule](https://nodejs.org/en/about/releases/). Here's [apost on why we think this is important](https://medium.com/the-node-js-collection/maintainers-should-consider-following-node-js-release-schedule-ab08ed4de71a).
## Special Thanks
The yargs project evolves from optimist and minimist. It owes itsexistence to a lot of James Halliday's hard work. Thanks [substack](https://github.com/substack) **beep** **boop** \o/
## License
ISC
|
