iterFirst

Return the first iterated value.

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 );