function bifurcateBy( collection, opts, predicate ) {
	var thisArg;
	var bool;
	var out;
	var len;
	var v;
	var i;

	thisArg = opts.thisArg;
	len = collection.length;
	if ( len === 0 ) {
		return [];
	}
	out = [ [], [] ];
	for ( i = 0; i < len; i++ ) {
		v = collection[ i ];
		bool = predicate.call( thisArg, v, i );
		if ( bool ) {
			out[ 0 ].push( v );
		} else {
			out[ 1 ].push( v );
		}
	}
	return out;
}
Splits values into two groups according to a predicate function and outputs results as element values.

## Notes

-   We need to cache the collection value to prevent the edge case where, during the invocation of the predicate function, the element at index `i` is swapped for some other value. For some, that might be a feature; here, we take the stance that one should be less clever.

@private
@param {Collection} collection - input collection
@param {Options} opts - function options
@param {*} [opts.thisArg] - execution context
@param {Function} predicate - predicate function indicating which group an element in the input collection belongs to
@returns {(Array<Array>|Array)} results

@example
function predicate( v ) {
    return v[ 0 ] === 'b';
}
var arr = [ 'beep', 'boop', 'foo', 'bar' ];

var out = bifurcateBy( arr, {}, predicate );
// returns [ [ 'beep', 'boop', 'bar' ], [ 'foo' ] ]