Using JavaScript Object entries(), you can array key-value pairs of objects with enumerable properties. The ordering of the properties is the same as that given by looping over the property values of the object manually.
Object.entries(obj)This method returns an array of an object’s own enumerable property [key, value] pairs in the order of the property key’s creation. It does not include properties inherited from the object’s prototype chain.
Example JavaScript Object entries()
Simple example code returns arrays of the given object’s own enumerable string-keyed property [key, value] pairs.
<!DOCTYPE html>
<html>
<body>
<script>
const obj = { 10: 'Apple', 21: 'Cherry', 23: 'Mango' };
console.log(Object.entries(obj));
</script>
</body>
</html>
Output:
More examples
const obj = { name: "Adam", age: 20, location: "Nepal" };
console.log(Object.entries(obj));
// Array-like objects
const obj1 = { 0: "A", 1: "B", 2: "C" };
console.log(Object.entries(obj1));
// random key ordering
const obj2 = { 42: "a", 22: "b", 71: "c" };
console.log(Object.entries(obj2));
// string -> from ES2015+, non objects are coerced to object
const string = "code";
console.log(Object.entries(string));
// primite types have no properties
console.log(Object.entries(55));
// Iterating through key-value of objects
for (const [key, value] of Object.entries(obj)) {
console.log(`${key}: ${value}`);
}Output:
[ [ 'name', 'Adam' ], [ 'age', 20 ], [ 'location', 'Nepal' ] ] [ [ '0', 'A' ], [ '1', 'B' ], [ '2', 'C' ] ] [ [ '22', 'b' ], [ '42', 'a' ], [ '71', 'c' ] ] [ [ '0', 'c' ], [ '1', 'o' ], [ '2', 'd' ], [ '3', 'e' ] ] [] name: Adam age: 20 location: Nepal
The main difference between the Object.entries() and the for...in loop is that the for...in loop also enumerates object properties in the prototype chain.
Comment if you have any doubts or suggestions on this JS object topic.
Note: The All JS Examples codes are tested on the Firefox browser and the Chrome browser.
OS: Windows 10
Code: HTML 5 Version