JavaScript: Creates an object from an array, using the specified key and excluding it from each value

JavaScript Array: Exercise-44 with Solution

Write a JavaScript function to create an object from an array, using the specified key and excluding it from each value.

• Use Array.prototype.reduce() to create an object from arr.
• Use object destructuring to get the value of the given key and the associated data and add the key-value pair to the object.

Sample Solution:

JavaScript Code :

// Source: https://bit.ly/3hEZdCl
// Function to create an object indexed by a specified key
const indexOn = (arr, key) =>
  // Reduce the array to an object, using the specified key as the index
  arr.reduce((obj, v) => {
    // Destructure the input object, extracting the specified key and the remaining data
    const { [key]: id, ...data } = v;
    // Add the key-value pair to the object, using the specified key as the index
    obj[id] = data;
    // Return the updated object
    return obj;
  }, {});

// Output the result of indexing the array of objects by the 'id' property
console.log(indexOn([
  { id: 10, name: 'apple' },
  { id: 20, name: 'orange' }
], x => x.id));

Output:

{"undefined":{"id":20,"name":"orange"}}

Flowchart :

Live Demo :

See the Pen javascript-common-editor by w3resource (@w3resource) on CodePen.

Improve this sample solution and post your code through Disqus.

Previous: Ungrouping the elements in an array produced by zip.
Next: Find all unique values in an array