Use the Map.prototype.entries
function, like this
const m = new Map();
m.set('key1', {})
m.set('keyN', {})
console.log(m.entries().next().value); // [ 'key1', {} ]
If you want to get the first key, then use Map.prototype.keys
, like this
console.log(m.keys().next().value); // key1
Similarly if you want to get the first value, then you can use Map.prototype.values
, like this
console.log(m.values().next().value); // {}
The reason why we have to call next()
on the returned values is that, all those functions return iterators. Read more about the iteration protocol here.