Set and Map Methods

Set and Map Methods

Here are the most useful Set and Map methods together.

Set methods

const s = new Set();
s.add("x");      // add a value
s.has("x");      // true
s.delete("x");   // remove a value
s.clear();       // remove everything
s.size;          // how many values

Map methods

const m = new Map();
m.set("a", 1);   // add a pair
m.get("a");      // 1
m.has("a");      // true
m.delete("a");   // remove a pair
m.clear();       // empty the map
m.size;          // how many pairs

Iterating a Map

m.forEach(function(value, key) {
  console.log(key + " = " + value);
});

Iterating a Set

s.forEach(function(value) {
  console.log(value);
});

Keys and values of a Map

m.keys();   // the keys
m.values(); // the values
m.entries(); // key-value pairs

TL;DR

• Sets: add, has, delete, clear, size.
• Maps: set, get, has, delete, clear, size.
• forEach iterates both.
• Maps expose keys(), values(), entries().