while

Invoke a function while a test condition is true.

Usage

var whilst = require( '@stdlib/utils/while' );

whilst( predicate, fcn[, thisArg ] )

Invokes a function until a predicate function returns false.

function predicate( i ) {
    return ( i < 5 );
}

function beep( i ) {
    console.log( 'boop: %d', i );
}

whilst( predicate, beep );
/* =>
    boop: 0
    boop: 1
    boop: 2
    boop: 3
    boop: 4
*/

Both the predicate function and the function to invoke are provided a single argument:

  • i: iteration number (starting from zero)

To set the function execution context for the invoked function, provide a thisArg.

function predicate( i ) {
    return ( i < 5 );
}

function count() {
    this.count += 1;
}

var context = {
    'count': 0
};

whilst( predicate, count, context );

console.log( context.count );
// => 5

Examples

var randu = require( '@stdlib/random/base/randu' );
var whilst = require( '@stdlib/utils/while' );

function predicate() {
    return ( randu() > 0.05 );
}

function log( i ) {
    console.log( i );
}

whilst( predicate, log );