Wrong approach to dot notation?

Question

I have a object that looks like this:

var obj = {
   Laser: [0, 2],
   Missile: [4, 4]
}

using literal notation, i can access the properties just fine:

for (prop in obj){
console.log(prop + " scored " + obj[prop][0] + " out of " + obj[prop][1] + " shots.");

Why cant the same be said using dot-notation like this ?

for (prop in obj){
console.log(prop + " scored " + obj.prop[0] + " out of " + obj.prop[1] + " shots.");
-> error

thanks in advance

Answer 1

Because these two examples are not the same. The first one is ok:

prop == "Laser"
obj[prop] == obj["Laser"]
obj["Laser"][0] === 0

prop == "Missile"
obj[prop] == obj["Missile"]
obj["Missile"][0] == 4

In the second one you are trying to access "prop" property, which is undefined:

obj.prop == obj["prop"]
obj["prop"] === undefined
obj["prop"][0] // TypeError: Cannot read property "0" of undefined

And, btw, this has nothing to do with JSON.