Get the Sum of all Values in a Map using JavaScript

Get the Sum of all Values in a Map #

To get the sum of all values in a Map:

1. Initialize a sum variable and set it to 0.
2. Use the forEach() method to iterate over the Map.
3. On each iteration, add the number to the sum, reassigning the variable.

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const map1 = new Map([
  ['key1', 1],
  ['key2', 2],
]);

let sum = 0;

map1.forEach(value => {
  sum += value;
});

console.log(sum); // 👉️ 3

The forEach method returns undefined, so we need to declare a variable where we can keep the state.

We used the Map() constructor to create a Map object, that consists of 2 key-value pairs.

The function we passed to the Map.forEach method gets called with 3 parameters:

• the value of the iteration
• the key of the iteration
• the Map object

We take the current value and add it to sum, reassigning the variable.

Further Reading #

• Check if a Map has an Object Key using JavaScript
• Get the Sum of all Numbers in a Set using JavaScript