How to use Map.has() and Map.set() Methods In Javascript

Method 2: Using Map.forEach() method

In this method, we will first check if the Map contains the specific key using the has() method. If the key is present, we will then use the set() method to update its value.

Example:

JavaScript

// Creating a map object 
let m = new Map([ 
    ["a", 100], 
    ["b", 200], 
]); 

// Display old value 
console.log("Old value for key: 'b', " + m.get("b")); 

// Check if the key exists and update the value
if (m.has("b")) {
    m.set("b", 1000);
}

// Display updated value 
console.log("New value for key: 'b', " + m.get("b"));

Output

Old value for key: 'b', 200
New value for key: 'b', 1000

In this example, we will update the value of key (‘b’) in the given map only if it exists, using the has() and set() methods.

JavaScript Program to Update the Value for a Specific Key in Map

In this article, we will see different approaches to update the value for a specific key in Map in JavaScript. JavaScript Map is a collection of key-value pairs. We have different methods to access a specific key in JavaScript Map.