How can I retrieve property values as an array from an array of objects in JavaScript?

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1

I am working with an array of JavaScript objects structured as follows:

objectArray = [ { alpha: 10, beta: 20}, { alpha: 30, beta: 40}, { alpha: 50, beta: 60} ];

My goal is to extract one specific property from each object and compile these values into a new array. For example, extracting the alpha property should yield [10, 30, 50].

Currently, I achieve this using a simplistic method:

function extractProperty(arr, prop) {
    let values = [];
    for (let j = 0; j < arr.length; j++)
        values.push(arr[j][prop]);
    return values;
}

const alphaValues = extractProperty(objectArray, "alpha"); // outputs [10, 30, 50]

Is there a more concise or idiomatic approach to achieve this without relying on a custom utility function?

Note that a suggested duplicate question involves transforming a single object into an array, which does not apply here.

2

To achieve the extraction of a specific property from each object within a JavaScript array in a more concise manner, you can utilize the map method. The map function is a built-in feature of JavaScript arrays that allows you to transform each element within an array, and it is ideally suited for this task. Here’s how you can implement this approach:

Code Example:

const objectArray = [
  { alpha: 10, beta: 20 },
  { alpha: 30, beta: 40 },
  { alpha: 50, beta: 60 },
];

const extractProperty = (arr, prop) => arr.map(obj => obj[prop]);

const alphaValues = extractProperty(objectArray, 'alpha');
console.log(alphaValues); // Outputs: [10, 30, 50]

Explanation:

  • Arrow Function: Here, extractProperty is defined as an arrow function. It takes an array arr and a string prop as parameters.
  • map Method: The function leverages the map method to iterate over each object in the objectArray, applying the transformation function obj => obj[prop] to retrieve the property value specified by prop from each object.
  • Conciseness: This method eliminates the need for explicit loops and temporary arrays, providing a clean and efficient way to achieve the objective.

This approach is both idiomatic and leverages modern JavaScript features, making your code more readable and maintainable.

3

Hey there! Use map for a quick solution:

const alphaValues = objectArray.map(({ alpha }) => alpha);
4

Hey there, fellow coder! :tada: Let’s try another nifty way to extract a property from an array of objects in JavaScript using destructuring within the map function. Check this out:

const objectArray = [
  { alpha: 10, beta: 20 },
  { alpha: 30, beta: 40 },
  { alpha: 50, beta: 60 },
];

const alphaValues = objectArray.map(({ alpha }) => alpha);

console.log(alphaValues); // [10, 30, 50]

By destructuring the alpha property directly during the map, your code becomes super clean and expressive—nice, right? Shoot me a question if you need more help!

5

Certainly! If you’re looking to extract a certain property from each object in a JavaScript array efficiently, let’s keep it straightforward with map, while emphasizing clarity.

Here’s a simple and clean way to do it:

const objectArray = [
  { alpha: 10, beta: 20 },
  { alpha: 30, beta: 40 },
  { alpha: 50, beta: 60 },
];

// Extract 'alpha' property directly using map
const alphaValues = objectArray.map(obj => obj.alpha);

console.log(alphaValues); // Outputs: [10, 30, 50]

Why This Works:

  • map Functionality: map is a built-in JavaScript function that processes each item in an array, returning a new array of values. Here, it’s perfect for creating an array of specific property values.
  • Simplicity: The direct use of map keeps the code simple and readable.

This method saves you from writing additional functions or loops, achieving your goal in a clean manner. Feel free to ask if you have more questions or need further assistance!