如何循环遍历数组并为每个项目分配一个没有循环的值？

Question

I have an array of object like so:

let data = [{Date : null, id: null}, {Date : null, id: null}, {Date : null, id: null}]

And i need to assign every Date property a value. I did it with a loop

let dates = ['2022-01-01','2022-02-02','2020-02-03']
for (let i=0; i<dates.length; i++) {
  data[i].Date = dates[i]
}

But i was wondering is it possible to do with one line? I was trying to use something like this, but it didn't work.

 data.map((i)=>{
  data[i].Date = dates[i]
 })

Because i doenst hold index but a value. Is it possible to use i as index iterator in map?

Answer 1

map() creates a new array, if you want to alter data , use forEach so you can get the current index to find the desired value in dates

data.forEach((d, i) => d.Date = dates[i]);

---

 let data = [{Date: null, id: null}, {Date: null, id: null}, {Date: null, id: null}]; let dates = ['2022-01-01','2022-02-02','2020-02-03']; data.forEach((d, i) => d.Date = dates[i]); console.log(data);

Answer 2

You can do it more functional, in a cleaner way by using map...

 let data = [{Date: null, id: null}, {Date: null, id: null}, {Date: null, id: null}]; let dates = ['2022-01-01','2022-02-02','2020-02-03']; const newData = data.map((a, i) => ({Date: dates[i], id: a.id})); console.log(newData);