Get value from dynamic list of object using javascript

Question

Seeking the below result with dynamic list of object using javascript. Defined approach getting me undefined index of value.

Javascript Code

var obj = {};
var obj_ = {
  "clist_1": "abc",
  "clist_2": "def",
  "branch_1": "efg"
}
for (let key in obj_) {
  if (key.includes("clist_")) {
    let num = key.replace(/^\D+/g, '');
    obj[num] = obj_.key;
  }
}

console.log(obj)

Desired Result

{
  "1": "abc",
  "2": "def"
}

`obj_[key];` instead of `obj_.key;` - I can't believe this isn't a duplicate of about 100 questions — Jaromanda X, Mar 28 '19 at 14:54
@JaromandaX I confess I used Google, never tried using SO's own search :) As you say there are loads I could have marked this as a dupe of — Robin Zigmond, Mar 28 '19 at 14:57
@JaromandaX It might be is duplicate which i have posted here but sometime it happening with person was not be able to search exact indenfied thing which he has needed. Thankyou for you support its really helpful for me — Query Master, Mar 28 '19 at 15:05
Oh, @QueryMaster - I'm with you, I could not find the duplicate — Jaromanda X, Mar 28 '19 at 15:08

R3tep · Accepted Answer · 2019-03-28T14:56:27.847

3

You can use bracket notation. You need to do obj_[key] and not obj_.key.

var obj = {};
var obj_ = {
  "clist_1": "abc",
  "clist_2": "def",
  "branch_1": "efg"
}
for (let key in obj_) {
  if (key.includes("clist_")) {
    let num = key.replace(/^\D+/g, '');
    obj[num] = obj_[key];
  }
}

console.log(obj)

edited Mar 28 '19 at 14:56

answered Mar 28 '19 at 14:52

R3tep

12,512
10
48
75

score 1 · Answer 2 · answered Mar 28 '19 at 14:52

You need a property accessor in bracket notation for the key.

obj[num] = obj_[key];
//             ^^^^^

Then you could use startsWith instead of includes for checking the starting part of a string.

var obj = {};
var obj_ = {
  "clist_1": "abc",
  "clist_2": "def",
  "branch_1": "efg"
}
for (let key in obj_) {
  if (key.startsWith("clist_")) {
    let num = key.replace(/^\D+/g, '');
    obj[num] = obj_[key];
  }
}

console.log(obj);

score 0 · Answer 3 · answered Mar 28 '19 at 14:56

0

Alternative chain way:

var obj = {};
var obj_ = {
  "clist_1": "abc",
  "clist_2": "def",
  "branch_1": "efg"
};

Object.keys(obj_)
    .map(key=>key.replace(/^\D+/g, ''))
    .map(key=>obj[key]=obj_[key]);

console.log(obj);

answered Mar 28 '19 at 14:56

Zydnar

1,472
18
27

score 0 · Answer 4 · answered Mar 28 '19 at 15:10

0

You can do:

const obj_ = {"clist_1": "abc","clist_2": "def","branch_1": "efg"};
const obj = Object.keys(obj_)
  .filter(k => k.startsWith('clist_'))
  .reduce((a, c) => (a[c.match(/\d+/g)] = obj_[c], a), {});
  
console.log(obj);

answered Mar 28 '19 at 15:10

Yosvel Quintero

18,669
5
37
46

Get value from dynamic list of object using javascript

4 Answers4