Array.from vs Array.prototype.map

Question

So what is the difference between this two functions?

They both create new Array object. Only difference I found so far is that Array.from supp

Answer 1

Array.map seems to be a bit more performant as well:

var a = () => [{"count": 3},{"count": 4},{"count": 5}].map(item => item.count);
var b = () => Array.from([{"count": 3},{"count": 4},{"count": 5}], x => x.count);

var iterations = 1000000;
console.time('Function #1');
for(var i = 0; i < iterations; i++ ){
    b();
};
console.timeEnd('Function #1')

console.time('Function #2');
for(var i = 0; i < iterations; i++ ){
    a();
};
console.timeEnd('Function #2')

Running this code using Chrome (Version 65.0.3325.181) on this page gave me the follow results:

Function #1: 520.591064453125ms
Function #2: 33.622802734375ms