javascript - 将数字转换为对应的字母

Question

function numObj(s){
  var emptyObj = {};
    s.forEach(function(num) {
      emptyObj[num] = String.fromCharCode(num);
   }); 
  return emptyObj;
}
console.log(numObj([118,117,120]));

我正在编写这个函数来将 int 转换为字母表中相应的 char。然而， 我期待输出 {'118': 'v', '117': 'u', '120': 'x' }，但是当我运行代码时，我得到: { '117': 'u', '118': 'v', '120': 'x' } .有谁有任何解释为什么该函数会改变输入的顺序？

Answer 1

参见Does JavaScript Guarantee Object Property Order? , Nailing object property order

使用Map()

function numObj(s){
  let emptyObj = new Map();
    s.forEach(function(num) {
      emptyObj.set(num, {[num]:String.fromCharCode(num)});
   }); 
  return emptyObj;
}
let obj = numObj([118,117,120]);

for (let [key, value] of obj.entries()) {
  console.log(key, value)
}

或Array()来存储对象

function numObj(s){
  let emptyObj = Array.from({length:s.length});
    s.forEach(function(num, i) {
      emptyObj[i] = {[num]:String.fromCharCode(num)};
   }); 
  return emptyObj;
}
let obj = numObj([118,117,120]);

for (let [key, value] of obj.entries()) {
  console.log(key, value)
}