function ifelseAsync( predicate, x, y, done ) {
	if ( !isFunction( predicate ) ) {
		throw new TypeError( format( 'invalid argument. First argument must be a function. Value: `%s`.', predicate ) );
	}
	if ( !isFunction( done ) ) {
		throw new TypeError( format( 'invalid argument. Last argument must be a function. Value: `%s`.', done ) );
	}
	predicate( clbk );

	/**
	* Callback invoked by a predicate function.
	*
	* @private
	* @param {(Error|null)} error - error object
	* @param {boolean} bool - condition
	* @returns {void}
	*/
	function clbk( error, bool ) {
		if ( error ) {
			return done( error );
		}
		if ( bool ) {
			return done( null, x );
		}
		done( null, y );
	}
}
If a predicate function returns a truthy value, returns `x`; otherwise, returns `y`.

@param {Function} predicate - predicate function
@param {*} x - value to return if a condition is truthy
@param {*} y - value to return if a condition is falsy
@param {Function} done - callback to invoke upon completion
@throws {TypeError} first argument must be a function
@throws {TypeError} last argument must be a function

@example
var randu = require( '@stdlib/random/base/randu' );

function predicate( clbk ) {
    setTimeout( onTimeout, 0 );
    function onTimeout() {
        clbk( null, randu() > 0.5 );
    }
}

function done( error, result ) {
    if ( error ) {
        throw error;
    }
    console.log( result );
}
ifelseAsync( predicate, 1.0, -1.0, done );