Map.prototype.set()

{{JSRef}} 

The set() method of {{jsxref("Map")}}  instances adds or updates an entry in this map with a specified key and a value.

{{InteractiveExample("JavaScript Demo: Map.prototype.set()")}} 

const map1 = new Map();
map1.set("bar", "foo");

console.log(map1.get("bar"));
// Expected output: "foo"

console.log(map1.get("baz"));
// Expected output: undefined

Syntax

set(key, value)

Parameters

• key
  • : The key of the element to add to the Map object. The key may be any JavaScript type (any primitive value or any type of JavaScript object).
• value
  • : The value of the element to add to the Map object. The value may be any JavaScript type (any primitive value or any type of JavaScript object).

Return value

The Map object.

Examples

Using set()

const myMap = new Map();

// Add new elements to the map
myMap.set("bar", "foo");
myMap.set(1, "foobar");

// Update an element in the map
myMap.set("bar", "baz");

Using the set() with chaining

Since the set() method returns back the same Map object, you can chain the method call like below:

// Add new elements to the map with chaining.
myMap.set("bar", "foo").set(1, "foobar").set(2, "baz");

Specifications

{{Specifications}} 

Browser compatibility

{{Compat}} 

See also

• {{jsxref("Map")}} 
• {{jsxref("Map.prototype.get()")}} 
• {{jsxref("Map.prototype.has()")}}