[Easy] fromPairs

Question Prompt

Implement a function named fromPairs that takes a single argument, pairs, which is an array of two-element sub-arrays. Each sub-array represents a key-value pair, where the first element is the key (string or symbol) and the second element is the value (any valid JavaScript data type). Your function should return a new object where each key-value pair from the pairs array is added as a property-value pair to the object.

const pairs = [
  ["explain", "this"],
  ["help", "you"],
  ["keep", "growing"],
];

fromPairs(pairs);
// => { explain: 'this', help: 'you', keep: 'growing' }

Solutions

we can begin by creating an empty object result to store the final key-value pairs. This object will serve as the foundation for our transformed data.

Then, we can use for...of loop, to efficiently iterate through each element in the pairs array. And use destructuring assignment ([key, value]) to elegantly extract the key and value from each sub-array within the loop.

And through result[key] = value, we dynamically create a new property in the result object with the extracted key and assign the corresponding value to it. Finally, return the populated result object, representing the transformed data structure

function fromPairs(pairs) {
  const result = {};

  for (const [key, value] of pairs) {
    result[key] = value;
  }

  return result;
}

This one can also be done by leveraging the JavaScript Object.fromEntries. We can simply do the following

function fromPairs(pairs) {
  return Object.fromEntries(pairs);
}