int.js

//1. native operators, best looking but depends on primitive types or operator overloading
if (1 + 5 - 2 <= 9) return;

//2. methods, correct java-inspired design employed by most modules
if (int(1).add(5).subtract(2).lessThanOrEqualTo(9)) return;

//3. first custom design, works alongside 2
if (int(1)._("+", 5)._("-", 2)._("<=", 9)) return;

//4. current design, replaces others
if (int(1, "+", 5, "-", 2, "<=", 9)) return;

function int() at https://github.com/zootella/node/blob/master/measure.js#L374