.map() a Javascript ES6 Map?

Question

How would you do this? Instinctively, I want to do:

var myMap = new Map([[\"thing1\", 1], [\"thing2\", 2], [\"thing3\", 3]]);

// wishful, ignorant thinking
         


        

Answer 1

Map.prototype.map = function(callback) {
  const output = new Map()
  this.forEach((element, key)=>{
    output.set(key, callback(element, key))
  })
  return output
}

const myMap = new Map([["thing1", 1], ["thing2", 2], ["thing3", 3]])
// no longer wishful thinking
const newMap = myMap.map((value, key) => value + 1)
console.info(myMap, newMap)

Depends on your religious fervor in avoiding editing prototypes, but, I find this lets me keep it intuitive.