CODEWITHSUNDEEP
javascriptobjectkeyspread-syntax
Vahe
Vahe

Reputation: 1841

JavaScript - adding extra keys values to an object using spread operation or alternative approaches

Here is the code:

    let bucket = [[],[],[],[],[],[],[],[],[],[]];

    bucket = {...Object.keys(bucket)
                       .sort((a,b) => b-a)
                       .filter(key => key > 0)
                       .map(key => '-'+key), 
              ...bucket};

   console.log(bucket);

Problem: the first line of code is not adding the negative keys of the original bucket object into the object, with all properties (keys) having empty arrays as their corresponding value.

Bucket only shows its original properties and values after this line of code is evaluated

How can I get this to work?

Upvotes: 0

Views: 87

Answers (1)

Ori Drori
Ori Drori

Reputation: 191936

The Array.map() creates an array of strings with your negative keys, and they are overwritten when you spread the bucket array. Instead create pairs of [new key, []] convert to an object with Object.fromEntries(), and then spread them:

const bucket = [[],[],[],[],[],[],[],[],[],[]];

const result = {
  ...Object.fromEntries(
    Object.keys(bucket)
      .filter(key => key > 0)
      .sort((a, b) => b-a)
      .map(key => [-key, []])
  ),
  ...bucket};

console.log(result);

Upvotes: 1

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