rOACCT/node_modules/yargs-parser49c99f97fe9aissn4frontend
README.md
yargs-parser
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The mighty option parser used by yargs.
visit the yargs website for more examples, and thorough usage instructions.
<img width="250" src="https://raw.githubusercontent.com/yargs/yargs-parser/main/yargs-logo.png">
Example
sh npm i yargs-parser --save
js const 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!_
js const 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:
js const parse = require('yargs-parser') parse(['-f', 11, '--zoom', 55].join(' ')) // <-- array to string parse(['-f', 11, '--zoom', 55].map(String)) // <-- array of strings
Deno Example
As of v19 yargs-parser supports Deno:
typescript import 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:
js import 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 the yargs 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 provided in args. These features can be turned on and off using the configuration field of opts.
js var 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 and a 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 not configured 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. Here's a post on why we think this is important.
Special Thanks
The yargs project evolves from optimist and minimist. It owes its existence to a lot of James Halliday's hard work. Thanks substack beep boop \o/
License
ISC