Nested Object Loop in JS

Question

I'm trying to add a series of values to a nested object, having some trouble with the loop in the following code. Any help would be really appreciated.

let settings = {};

function write(id, values) {
    if(!settings[id]) settings[id] = {};
    for(var x = 0; x < Object.keys(values).length; x ++) {
        settings[id][values[x]] = values[values[x]];
    }
}

//example
write('example', {'prop1': 5, 'prop2': 10});

What is the expected output? values[x] is similar to values[0], values is an object. This will fail if values object dont have key 0 — kiranvj
– kiranvj, Commented Jan 17, 2022 at 6:29
It would be better if you could publish the original object and the expected result — A1exandr Belan
– A1exandr Belan, Commented Jan 17, 2022 at 6:33

skara9 · Accepted Answer · 2022-01-17 06:28:36Z

1

You're attempting to index the object values with x, which is a number. To loop through the keys of your object you can use a for...in loop:

function write(id, values) {
    if(!settings[id]) settings[id] = {};
    for(const key in values) {
        settings[id][key] = values[key];
    }
}

Another approach would be to use object destructuring:

function write(id, values) {
    settings[id] = { ...(settings[id] || {}), ...values };
}

answered Jan 17, 2022 at 6:28

skara9

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Comments

Nitheesh · Accepted Answer · 2022-01-17 06:31:18Z

0

values is an object. Accessing values[x] will return undefined.

You have to access it with the correct keys in that object as below.

let settings = {};

function write(id, values) {
  if (!settings[id]) settings[id] = {};
  const keys = Object.keys(values);
  for (var x = 0; x < keys.length; x++) {
    settings[id][keys[x]] = values[keys[x]];
  }
  console.log(settings)
}

//example
write('example', { 'prop1': 5, 'prop2': 10 });

edited Jan 17, 2022 at 6:31

answered Jan 17, 2022 at 6:24

Nitheesh

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Comments

Wai Ha Lee · Accepted Answer · 2022-01-17 15:48:29Z

0

try to keep the Object.keys(values) return in another variable and use it to assign value in setting like this

function write(id, values) {
    if(!settings[id]) settings[id] = {};
    const key = Object.keys(values) 
    for(var x = 0; x < key.length; x ++) {
        settings[id][key[x]] = values[key[x]];
    }
}

edited Jan 17, 2022 at 15:48

Wai Ha Lee

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answered Jan 17, 2022 at 6:42

Ilham Naufal

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