Computed property names allow you to create object properties with dynamic keys in ES6. Instead of specifying a fixed key name, an expression can be used to compute the property name at runtime.

When creating an object, you can write the keys as strings:

const character = {
  name: "Mario",
  occupation: "Plumber",
};

But what if we want to use a variable as the key name? This is where computed property names come in handy:

const character = {
  name: "Mario",
  occupation: "Plumber",
};

function getCharacter(character) {
  return {
    [character.name]: character.occupation,
  };
}

const mario = getCharacter(character);
console.log(mario); // { Mario: 'Plumber' }

The expression inside [] is evaluated and its result is used as the property name. In the example above, we use the name property of the character object as the key name for the new object. This allows us to create dynamic object properties, based on the values of other properties.