Short-Utils

strictEquals.js

//Write a function called strictEquals(a, b) that returns the same value as a === b. Your implementation must not use the === or !== operators.
function strictEquals(a, b){
  if (Number.isNaN(a) || Number.isNaN(b)){
    return false; 
  }
  //+0/-0
  if (isEqual(a, -0) && isEqual(b, +0) || isEqual(a, +0) && isEqual(b, -0)){
    return true;
  }
  return Object.is(a, b);
};

function isEqual(x, y) {
    var obj = {};
    Object.defineProperty(obj, 'z', { value: x, configurable: false });
    try {
        // 如果x的值和z属性的当前值不相等的话,就会抛出异常.
        Object.defineProperty(obj, 'z', { value: y });
    } catch (e) {
        return false
    };
    return true;
}