maps.md

// REGULAR OBJECTS (cannot have non-string keys)

// create empty object x 
x = {}

// create object y 
y = {id: 1}

// attempt to put y into x as the key with a value of 'amy'
x[y] = 'amy'

// log x and see that y got stringified to "obejct Object" 
x // {[object Object]: "amy"}

// create object z 
z = {id: 2}

// attempt to put z into x as the key with a value of 'swift'
x[z] = 'swift'

// log x and see that z was also stringified to "object Object"
// this meant the already existing "object Object" key was accessed 
// and its value set to 'swift'
x // {[object Object]: "swift"}

// MAPS (can have non-string keys)

x = new Map()

y = {id: 1}
x.set(y, 'amy')
x.size // 1

z = {id: 2} 
x.set(z, 'swift')
x.size // 2