---
title: "Args"
description: "Learn about the Args package and its capabilities"
canonical: https://bomb.sh/docs/args/api/
---

# Args

The `@bomb.sh/args` package is a <1kB library for parsing CLI flags. Inspired by Deno's `std/cli` [`parseArgs`](https://github.com/denoland/std/blob/main/cli/parse_args.ts) module.

## Features

🤏 very small

🍃 very simple

🏃 very fast (beats [`node:util`](https://nodejs.org/api/util.html#utilparseargsconfig))

🔏 strongly typed

## Parsing the arguments

```ts
import { parse } from "@bomb.sh/args"

const args = parse(process.argv, {
  default: { a: 1, b: 2, c: "value" },
  alias: { h: "help" },
  boolean: ["foo", "bar"],
  string: ["baz", "qux"],
  array: ["input"],
});
```

* The first parameter is the raw CLI parameters list (in most case, it will be `process.argv`)
* The second parameter is the (optional) configuration to parse raw CLI parameters

> **Note:**
>
> In this documentation,
> the term option indicate a string prefixed by one or two hyphen (`-`),
> the term argument indicate a string that is not prefixed by hyphen:
>
> * `--long`: is an option (long variant), named `long`
> * `-l`: is an option (short variant), named `l`
> * `hello-world`: is an argument, its value is `hello-world`
>
> ***
>
> the term flag indicate an option that take two value: `true` or `false`

### Parse options

#### `default` option

It provides the default value to set if the option is missing

```ts
import { parse } from "@bomb.sh/args"

const args = parse(process.argv, {
  default: { a: 1, b: 2, c: "value" },
});
```

the variable `args` will be equals to (assuming CLI parameters are `my-command --a=27`):

```js
args = {
    _: [],
    a: 27,
    b: 2,
    c: 'value'
}
```

#### `alias` option

It offers an alternative name for an option.
The object key is the alternative name, the value the name used in the parsing result

```ts
import { parse } from "@bomb.sh/args"

const args = parse(process.argv, {
  alias: { h: 'help' },
});
```

the variable `args` will be equals to (assuming CLI parameters are `my-command -h`):

```js
args = {
    _: [],
    help: true
}
```

#### `boolean` option

Indicate that an option is flag, and so argument after it **is not** its value

```ts
import { parse } from "@bomb.sh/args"

const args = parse(process.argv, {
  boolean: ['get'],
});
```

the variable `args` will be equals to (assuming CLI parameters are `my-command --get http://my-url.com`):

```js
args = {
    _: ['http://my-url.com'],
    get: true
}
```

#### `string` option

Indicate that an option have a value, and so the argument after it is its value (or an empty string is none is available)

```ts
import { parse } from "@bomb.sh/args"

const args = parse(process.argv, {
  string: ['get', 'user'],
});
```

the variable `args` will be equals to (assuming CLI parameters are `my-command --user --get http://my-url.com`):

```js
args = {
    _: [],
    user: '',
    get: 'http://my-url.com'
}
```

#### `array` option

Indicate that an option have a value and can be repeated several times

```ts
import { parse } from "@bomb.sh/args"

const args = parse(process.argv, {
  array: ['tag'],
});
```

the variable `args` will be equals to (assuming CLI parameters are `my-command --tag app:v1 --tag app:latest`):

```js
args = {
    _: [],
    tag: ['app:v1', 'app:latest']
}
```

### Special option

#### Negation variant

If a boolean option is prefixed by `--no-` it will parse as a `false` flag (without the `no-` prefix)

```ts
import { parse } from "@bomb.sh/args"

const args = parse(process.argv);
```

the variable `args` will be equals to (assuming CLI parameters are `my-command --no-color`):

```js
args = {
    _: [],
    color: false
}
```

> **Note:**
>
> If the option is defined as a `string` this behavior is ignored
>
> ```ts
> import { parse } from "@bomb.sh/args"
>
> const args = parse(process.argv, { string: ['no-name'] });
> ```
>
> the variable `args` will be equals to (assuming CLI parameters are `my-command --no-color --no-name John`):
>
> ```js
> args = {
>     _: [],
>     'color': false
>     'no-name': 'John'
> }
> ```