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denoland-deno/std/flags/README.md
Nayeem Rahman f184332c09
BREAKING(std): reorganization (#5087)
* Prepend underscores to private modules
* Remove collectUint8Arrays() It would be a misuse of Deno.iter()'s result.
* Move std/_util/async.ts to std/async
* Move std/util/sha*.ts to std/hash
2020-05-09 08:34:47 -04:00

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# flags
Command line arguments parser for Deno based on minimist
# Example
```ts
const { args } = Deno;
import { parse } from "https://deno.land/std/flags/mod.ts";
console.dir(parse(args));
```
```
$ deno run https://deno.land/std/examples/flags.ts -a beep -b boop
{ _: [], a: 'beep', b: 'boop' }
```
```
$ deno run https://deno.land/std/examples/flags.ts -x 3 -y 4 -n5 -abc --beep=boop foo bar baz
{ _: [ 'foo', 'bar', 'baz' ],
x: 3,
y: 4,
n: 5,
a: true,
b: true,
c: true,
beep: 'boop' }
```
# API
## const parsedArgs = parse(args, options = {});
`parsedArgs._` contains all the arguments that didn't have an option associated
with them.
Numeric-looking arguments will be returned as numbers unless `options.string` or
`options.boolean` is set for that argument name.
Any arguments after `'--'` will not be parsed and will end up in `parsedArgs._`.
options can be:
- `options.string` - a string or array of strings argument names to always treat
as strings
- `options.boolean` - a boolean, string or array of strings to always treat as
booleans. if `true` will treat all double hyphenated arguments without equal
signs as boolean (e.g. affects `--foo`, not `-f` or `--foo=bar`)
- `options.alias` - an object mapping string names to strings or arrays of
string argument names to use as aliases
- `options.default` - an object mapping string argument names to default values
- `options.stopEarly` - when true, populate `parsedArgs._` with everything after
the first non-option
- `options['--']` - when true, populate `parsedArgs._` with everything before
the `--` and `parsedArgs['--']` with everything after the `--`. Here's an
example:
```ts
// $ deno run example.ts -- a arg1
const { args } = Deno;
import { parse } from "https://deno.land/std/flags/mod.ts";
console.dir(parse(args, { "--": false }));
// output: { _: [ "a", "arg1" ] }
console.dir(parse(args, { "--": true }));
// output: { _: [], --: [ "a", "arg1" ] }
```
- `options.unknown` - a function which is invoked with a command line parameter
not defined in the `options` configuration object. If the function returns
`false`, the unknown option is not added to `parsedArgs`.