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@license Apache-2.0

Copyright (c) 2019 The Stdlib Authors.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

   http://www.apache.org/licenses/LICENSE-2.0

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distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# Help

> Return help text associated with a provided alias.

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<section class="intro">

</section>

<!-- /.intro -->

<!-- Package usage documentation. -->

<section class="usage">

## Usage

```javascript
var help = require( '@stdlib/repl/help' );
```

#### help( alias )

Returns help text for a provided alias.

```javascript
var txt = help( 'base.sin' );
// returns <string>
```

If provided an unrecognized `alias`, the function returns `null`.

```javascript
var txt = help( 'unrecognized_alias_beep_boop_bop_bip' );
// returns null
```

</section>

<!-- /.usage -->

<!-- Package usage notes. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->

<section class="notes">

</section>

<!-- /.notes -->

<!-- Package usage examples. -->

<section class="examples">

## Examples

<!-- TODO: better example -->

<!-- eslint no-undef: "error" -->

```javascript
var discreteUniform = require( '@stdlib/random/base/discrete-uniform' );
var aliases = require( '@stdlib/namespace/aliases' );
var help = require( '@stdlib/repl/help' );

var list;
var len;
var idx;
var i;

list = aliases();
len = list.length;

for ( i = 0; i < 100; i++ ) {
    idx = discreteUniform( 0, len-1 );
    console.log( help( list[ idx ] ) );
}
```

</section>

<!-- /.examples -->

<!-- Section for describing a command-line interface. -->



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<section class="references">

</section>

<!-- /.references -->

<!-- <license> -->

## License

The data files (databases) are licensed under an [Open Data Commons Public Domain Dedication & License 1.0][pddl-1.0] and their contents are licensed under [Creative Commons Zero v1.0 Universal][cc0]. The software is licensed under [Apache License, Version 2.0][apache-license].

<!-- </license> -->

<!-- Section for related `stdlib` packages. Do not manually edit this section, as it is automatically populated. -->

<section class="related">

## See Also

-   <span class="package-name">[`@stdlib/repl-cli`][@stdlib/repl-cli]</span><span class="delimiter">: </span><span class="description">CLI package for use as a command-line utility.</span>


</section>

<!-- /.related -->

<!-- Section for all links. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->

<section class="links">

[@stdlib/repl-cli]: https://www.npmjs.com/package/@stdlib/repl-cli

[pddl-1.0]: http://opendatacommons.org/licenses/pddl/1.0/

[cc0]: https://creativecommons.org/publicdomain/zero/1.0

[apache-license]: https://www.apache.org/licenses/LICENSE-2.0

</section>

<!-- /.links -->
