Object.entries()

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.

El método Object.entries() devuelve una matriz de pares propios de una propiedad enumerable [key, value] de un objeto dado, en el mismo orden que es proporcionado por for...in (La diferencia es que un bucle for-in enumera las propiedades en la cadena de prototipos).

Sintaxis

Object.entries(obj)

Parámetros

obj

The object whose enumerable own property [key, value] pairs are to be returned.

Valor de retorno

An array of the given object's own enumerable property [key, value] pairs.

Descripción

Object.entries() returns an array whose elements are arrays corresponding to the enumerable property [key, value] pairs found directly upon object. The ordering of the properties is the same as that given by looping over the property values of the object manually.

Ejemplos

js
var obj = { foo: "bar", baz: 42 };
console.log(Object.entries(obj)); // [ ['foo', 'bar'], ['baz', 42] ]

// array like object
var obj = { 0: "a", 1: "b", 2: "c" };
console.log(Object.entries(obj)); // [ ['0', 'a'], ['1', 'b'], ['2', 'c'] ]

// array like object with random key ordering
var an_obj = { 100: "a", 2: "b", 7: "c" };
console.log(Object.entries(an_obj)); // [ ['2', 'b'], ['7', 'c'], ['100', 'a'] ]

// getFoo is property which isn't enumerable
var my_obj = Object.create(
  {},
  {
    getFoo: {
      value: function () {
        return this.foo;
      },
    },
  },
);
my_obj.foo = "bar";
console.log(Object.entries(my_obj)); // [ ['foo', 'bar'] ]

// non-object argument will be coerced to an object
console.log(Object.entries("foo")); // [ ['0', 'f'], ['1', 'o'], ['2', 'o'] ]

// iterate through key-value gracefully
var obj = { a: 5, b: 7, c: 9 };
for (var [key, value] of Object.entries(obj)) {
  console.log(key + " " + value); // "a 5", "b 7", "c 9"
}

// Or, using array extras
Object.entries(obj).forEach(([key, value]) => {
  console.log(key + " " + value); // "a 5", "b 7", "c 9"
});

Converting an Object to a Map

The new Map() constructor accepts an iterable of entries. With Object.entries, you can easily convert from Object to Map:

js
var obj = { foo: "bar", baz: 42 };
var map = new Map(Object.entries(obj));
console.log(map); // Map { foo: "bar", baz: 42 }

Polyfill

To add compatible Object.entries support in older environments that do not natively support it, you can find a Polyfill in the tc39/proposal-object-values-entries or in the es-shims/Object.entries repositories.

Especificaciones

Specification
ECMAScript Language Specification
# sec-object.entries

Compatibilidad con navegadores

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See also