How to Efficiently Extract a Property Value as an Array from an Array of Objects in JavaScript?

How to Extract Value of a Property as Array from an Array of Objects

In JavaScript, you may encounter situations where you need to extract a specific property value from each object in an array. One way to accomplish this is through a custom function, as shown below:

const objArray = [{ foo: 1, bar: 2 }, { foo: 3, bar: 4 }, { foo: 5, bar: 6 }];

function getFields(input, field) {
  const output = [];
  for (let i = 0; i < input.length; ++i) {
    output.push(input[i][field]);
  }
  return output;
}

const result = getFields(objArray, "foo"); // returns [ 1, 3, 5 ]

However, there are more concise and idiomatic approaches using JavaScript's array methods:

1. Array.prototype.map():

   This method creates a new array with the results of calling a provided function on every element in the calling array. For your use case:

   const result = objArray.map(a => a.foo);

2. Array.prototype.map() with Destructuring:

   Using destructuring within the map function allows you to extract specific properties more concisely:

   const result = objArray.map(({ foo }) => foo);

These methods provide a cleaner and more efficient way to extract property values without the need for custom functions.

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