JavaScript computed property of object

A computed property in a JavaScript object is a way to dynamically define property keys using an expression inside square brackets ([]). This allows the key to be evaluated at runtime, making it possible to create properties based on variables, function calls, or other expressions. Here’s an example:

const keyName = 'dynamicKey';
const obj = {
  [keyName]: 'value'
};

console.log(obj.dynamicKey); // Output: value

In this example:

• The property key dynamicKey is computed using the variable keyName.
• When obj is created, keyName is evaluated, resulting in a property dynamicKey with the value "value".

Common Use Cases

1. Creating properties based on variable values:

function createObject(propName, value) {
  return {
    [propName]: value
  };
}

const newObj = createObject('name', 'Alice');
console.log(newObj.name); // Output: Alice

2. Using expressions for dynamic keys:

const obj = {
  ['prop_' + (1 + 2)]: 'Computed Property'
};

console.log(obj.prop_3); // Output: Computed Property

Summary

Computed properties provide flexibility by allowing you to define object keys based on dynamic conditions or values at runtime.