look up map js code example
Example: initialize a map js
let map = new Map()
map['bla'] = 'blaa'
map['bla2'] = 'blaaa2'
console.log(map) // Map { bla: 'blaa', bla2: 'blaaa2' }
let map = new Map()
map['bla'] = 'blaa'
map['bla2'] = 'blaaa2'
console.log(map) // Map { bla: 'blaa', bla2: 'blaaa2' }