How to Filter Object Properties by Key in ES6?

Filtering Object Properties by Key in ES6

In JavaScript, it's often necessary to filter object properties based on specific criteria. ES6 provides a clean and efficient way to achieve this through spread operators.

Problem:

Given an object like:

{
  item1: { key: 'sdfd', value: 'sdfd' },
  item2: { key: 'sdfd', value: 'sdfd' },
  item3: { key: 'sdfd', value: 'sdfd' }
}

The goal is to create a new object that only includes properties with specific keys, such as:

{
  item1: { key: 'sdfd', value: 'sdfd' },
  item3: { key: 'sdfd', value: 'sdfd' }
}

Solution:

ES6 allows us to filter object properties using a combination of the Object.keys() and Array.filter() methods, followed by the Array.reduce() method to create the new object.

The provided code demonstrates this approach:

const raw = {
  item1: { key: 'sdfd', value: 'sdfd' },
  item2: { key: 'sdfd', value: 'sdfd' },
  item3: { key: 'sdfd', value: 'sdfd' }
};

const allowed = ['item1', 'item3'];

const filtered = Object.keys(raw)
  .filter(key => allowed.includes(key))
  .reduce((obj, key) => {
    obj[key] = raw[key];
    return obj;
  }, {});

console.log(filtered);

In this code:

1. Object.keys(raw) extracts the object keys into an array.
2. Array.filter(key => allowed.includes(key)) filters the keys based on the allowed values.
3. Array.reduce((obj, key) => { /* ... */ }, {}) reduces the filtered keys into a new object, copying the corresponding property values from the original object.

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