Object keys, values and entries

Object methods such as keys, values and entries are not difficult to understand. In this example we need to create an object with key-value pairs.

//
//key: value
const numbers = {
  one: 1,
  two: 2,
  three: 3
};
//

Object.keys()

This method will simply return all the keys of the given object. In this example the output should be an array containing one, two, three.

//
console.log(Object.keys(numbers)); //one, two, three
//

Object.values()

Same logic as keys method but instead of keys we get an array containing object’s values.

//
console.log(Object.values(numbers); //1, 2, 3
//

Object.entries()

With this method the output will be slightly different and larger. Because this method will return both, the keys and the values as a single array for each key-value pair. To get each key and value after using the entries method we can use a for of loop and loop through the entries getting every single key and value as one pair.

//

const entries = Object.entries(numbers);

console.log(entries); // ["one", 1], ["two", 2], ["three", 3]

for (const [key, value] of entries) {
  console.log(`${key}: ${value}`); //one: 1 two: 2 three: 3
}

//