Returns a value as comparer.

A comparer has the following structure:

function (x, y) : number;

Examples

// x == y
var comparer1 = Enumerable.toComparerSafe();

// from Lambda
var comparer2 = Enumerable.toComparerSafe('(x, y) => y - x');

// from function
var comparer3 = Enumerable.toComparerSafe(function(x, y) {
    return y - x;
});

// THROWS EXCEPTION
Enumerable.toComparerSafe('test');