README

iterFirst

Return the first iterated value.

Installation

npm install @stdlib/iter-first

Usage

var iterFirst = require( '@stdlib/iter-first' );

iterFirst( iterator )

Returns the first iterated value.

var array2iterator = require( '@stdlib/array-to-iterator' );

var arr = array2iterator( [ 1, 0, 0, 0, 0 ] );

var v = iterFirst( arr );
// returns 1

If a provided iterator does not return any iterated values, the function returns undefined.

var iterEmpty = require( '@stdlib/iter-empty' );

var v = iterFirst( iterEmpty() );
// returns undefined

Notes

The function does not consume an entire iterator before returning.

Examples

var randu = require( '@stdlib/random-iter-randu' );
var iterMap = require( '@stdlib/iter-map' );
var iterFirst = require( '@stdlib/iter-first' );

function threshold( r ) {
    return ( r > 0.95 );
}

// Create an iterator which generates uniformly distributed pseudorandom numbers:
var opts = {
    'iter': 100
};
var riter = randu( opts );

// Create an iterator which applies a threshold to generated numbers:
var miter = iterMap( riter, threshold );

// Return the first threshold result:
var bool = iterFirst( miter );
// returns <boolean>

console.log( bool );

Notice

This package is part of stdlib, a standard library for JavaScript and Node.js, with an emphasis on numerical and scientific computing. The library provides a collection of robust, high performance libraries for mathematics, statistics, streams, utilities, and more.

For more information on the project, filing bug reports and feature requests, and guidance on how to develop stdlib, see the main project repository.

Community

License

See LICENSE.

@stdlib/iter-first

Usage no npm install needed!