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.
The Object.entries()
static method returns an array of a given object's own enumerable string-keyed property key-value pairs.
Try it
Syntax
Object.entries(obj)
Parameters
obj
-
An object.
Return value
An array of the given object's own enumerable string-keyed property key-value pairs. Each key-value pair is an array with two elements: the first element is the property key (which is always a string), and the second element is the property value.
Description
Object.entries()
returns an array whose elements are arrays corresponding to the enumerable string-keyed property key-value pairs found directly upon object
. This is the same as iterating with a for...in
loop, except that a for...in
loop enumerates properties in the prototype chain as well. The order of the array returned by Object.entries()
is the same as that provided by a for...in
loop.
If you only need the property keys, use Object.keys()
instead. If you only need the property values, use Object.values()
instead.
Examples
Using Object.entries()
const obj = { foo: "bar", baz: 42 };
console.log(Object.entries(obj)); // [ ['foo', 'bar'], ['baz', 42] ]
const arrayLike = { 0: "a", 1: "b", 2: "c" };
console.log(Object.entries(arrayLike)); // [ ['0', 'a'], ['1', 'b'], ['2', 'c'] ]
const randomKeyOrder = { 100: "a", 2: "b", 7: "c" };
console.log(Object.entries(randomKeyOrder)); // [ ['2', 'b'], ['7', 'c'], ['100', 'a'] ]
// getFoo is a non-enumerable property
const myObj = Object.create(
{},
{
getFoo: {
value() {
return this.foo;
},
},
},
);
myObj.foo = "bar";
console.log(Object.entries(myObj)); // [ ['foo', 'bar'] ]
Using Object.entries() on primitives
Non-object arguments are coerced to objects. undefined
and null
cannot be coerced to objects and throw a TypeError
upfront. Only strings may have own enumerable properties, while all other primitives return an empty array.
// Strings have indices as enumerable own properties
console.log(Object.entries("foo")); // [ ['0', 'f'], ['1', 'o'], ['2', 'o'] ]
// Other primitives except undefined and null have no own properties
console.log(Object.entries(100)); // []
Converting an Object to a Map
Iterating through an Object
Using array destructuring, you can iterate through objects easily.
// Using for...of loop
const obj = { a: 5, b: 7, c: 9 };
for (const [key, value] of Object.entries(obj)) {
console.log(`${key} ${value}`); // "a 5", "b 7", "c 9"
}
// Using array methods
Object.entries(obj).forEach(([key, value]) => {
console.log(`${key} ${value}`); // "a 5", "b 7", "c 9"
});
Specifications
Specification |
---|
ECMAScript Language Specification # sec-object.entries |
Browser compatibility
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