javascript从数字增加到字符串

Question

How can I parse number to string for increment? Do I have to make 2 line statement? Below code is not valid.

['a', 'b'].map((o,i)=>({myStr: ++i.toString()}))

ignore the array, it's just sample, I expect this [{myStr: "1"},{myStr:"2"}] where i is the index of map.

Answer 1

You have to wrap ++i : (++i).toString();

 const res = ['a', 'b'].map((o,i) => ({myStr: (++i).toString()} )); console.log(res); 

You can also use template literals:

  const res = ['a', 'b'].map((o,i) => ({myStr: `${++i}`} )); console.log(res); 

Answer 2

在String构造函数中包装++i ：

['a', 'b'].map((o,i)=>({myStr: String(++i)}))

Answer 3

 var arr = ['a', 'b'];
 var newArr = arr.map((o,i)=>({myStr: (++i).toString()}))