I've been told not to use for...in with arrays in JavaScript. Why not?...

How can I loop through all the entries in an array using JavaScript?  I thought it was something like this:  forEach(instance in theArray)   Where theArray is my array, but this seems to be incorrect....

I have an object which has inner objects and properties defined like this:  var obj = {obj1 : { "prop1" : "nothing", "prop2" : "prop"},         obj2 : {"prop1" : "nothing", "prop2" : "prop...

I have a dictionary that has the format of   dictionary = {0: {object}, 1:{object}, 2:{object}}   How can I iterate through this dictionary by doing something like  for((key,value) in dictionary){   //Do stuff where key would be 0 and value would b...

Say you have a javascript object like this:  var data = { foo: 'bar', baz: 'quux' };   You can access the properties by the property name:  var foo = data.foo; var baz = data["baz"];   But is it possible to get these values...

It maybe because Sets are relatively new to Javascript but I haven't been able to find an article, on StackO or anywhere else, that talks about the performance difference between the two in Javascript. So, what is the difference, in terms of pe...

How can I loop through all the entries in an array using JavaScript?  I thought it was something like this:  forEach(instance in theArray)   Where theArray is my array, but this seems to be incorrect....

This question already has answers here:...

Given an array having .length 100 containing elements having values 0 to 99 at the respective indexes, where the requirement is to find element of of array equal to n : 51.   Why is using a loop to iterate from start of array to end faster than itera...

Given the following algorithm:    console.log(JSON.stringify(create(0), null, 2))  function create(i) {   if (i == 5) return   return new Klass(i, create(i + 1), create(i + 1)) }  function Klass(i, l, r) {   this.i = i   this.l = l   this.r = r }...