for (const [ key, value ] of Object.entries(dictionary)) { // do something with `key` and `value` } Explanation: Object.entries() takes an object like { a: 1, b: 2, c: 3 } and turns it into an array of key-value pairs: [ [ 'a', 1 ], [ 'b', 2 ], [ 'c', 3 ] ] .

Jan 14, 2020 · There are two ways to add new properties to an object: key1: value1, key2: value2. The first form is used when you know the name of the property. The second form is used when the name of the property is dynamically determined. Like in this example: return obj[propertyName]; A real JavaScript array can be constructed using either: obj is an object.

Mar 7, 2025 · The Object.entries() static method returns an array of a given object's own enumerable string-keyed property key-value pairs.

Object.keys () returns the keys (properties) of any object type. Object.values () returns the values of all object keys (properties). Object.entries () returns the keys and values of any object types. The methods above return an Iterable (enumerable array). Iterables makes it simpler to use objects in loops and to convert objects into maps.

var obj = { 'bar' : 'baz' } var key = Object.keys(obj)[0]; var value = obj[key]; console.log("key = ", key) // bar console.log("value = ", value) // baz Object.keys() is a javascript method which return an array of keys when iterating over objects.

Jun 27, 2021 · Object.keys, values, entries. For plain objects, the following methods are available: Object.keys(obj) – returns an array of keys. Object.values(obj) – returns an array of values. Object.entries(obj) – returns an array of [key, value] pairs. Please note the distinctions (compared to map for example):

Nov 11, 2020 · How to Add a Key-Value Pair Using Bracket Notation in JavaScript. Just like dot notation, you can use bracket notation to add a key-value pair to an object. Bracket notation offers more flexibility than dot notation. That’s because key names can include spaces and hyphens, and they can start with numbers. I'll create an employee object below.

Mar 6, 2025 · Object.keys() returns an array whose elements are strings corresponding to the enumerable string-keyed property names found directly upon object. This is the same as …

Mar 3, 2022 · A JavaScript object contains key-value pairs. Depending on your use case you may need to iterate through all these key-value pairs. JavaScript offers different types of loops to iterate through the object. The allrounder is the for…in loop. …

Mar 6, 2025 · Objects allow you to set keys to values, retrieve those values, delete keys, and detect whether something is stored at a key. Map objects, however, have a few more advantages that make them better maps. The keys of an Object are strings or symbols, whereas they can be of any value for a Map.