I have array of objects, which need to add id in javascript.
function addKey(obj){
return obj.map(e=>({...e, id:index})
}
var obj=[
{name: "s1"},
{name: "s2"}
]
Expected Output
[
{name: "s1", id:0 },
{name: "s2", id:1 }
]
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2 Answers
using object.assign u can add key
var obj = [{
name: 's1'
}, {
name: 's2'
}];
var result = obj.map(function(el,index) {
var o = Object.assign({}, el);
o.id = index;
return o;
})
console.log(result);
1 Comment
Mr. Polywhirl
Why use
Object.assign when OP was already using spread syntax? e.g. { ...e, id: index }You can add an id property by adding the index of an Array.prototype.map callback.
const
obj = [
{ name: "s1" },
{ name: "s2" }
],
offset = 2;
console.log(obj.map((item, id) => ({ ...item, id: id + offset })));If you want to modify the object in-place (without polluting memory), you can try the following:
const
obj = [
{ name: "s1" },
{ name: "s2" }
],
offset = 2;
obj.forEach((item, index) => item.id = index + offset)
console.log(obj);
2 Comments
Mr. Polywhirl
@d'reaper I added an offset to show how to add it.