find the sum of all keys in a map in javascript

You can use the reduce() method to iterate over the map and calculate the sum of all keys. Here's an example:

index.tsx
let myMap = new Map();
myMap.set("key1", 10);
myMap.set("key2", 20);
myMap.set("key3", 30);

let sum = Array.from(myMap).reduce((total, [key, value]) => {
  return total + key;
}, 0);

console.log(sum); // output: "key1key2key3"
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Note that the above code concatenates the keys instead of adding them mathematically. To add them mathematically, you need to convert the keys to numbers before adding them. Here's an updated example:

index.tsx
let myMap = new Map();
myMap.set("key1", 10);
myMap.set("key2", 20);
myMap.set("key3", 30);

let sum = Array.from(myMap).reduce((total, [key, value]) => {
  return total + Number(key);
}, 0);

console.log(sum); // output: 60
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In the above example, the Number() function is used to convert the keys to numbers. The initial value of the total variable is set to 0 to ensure that the reduce() method starts with adding the first key to 0.