What is the scope of variables in javascript? Do they have the same scope inside as opposed to outside a function? Or does it even matter? Also, where are the variables stored if they are defined globally?...

I've recently started maintaining someone else's JavaScript code. I'm fixing bugs, adding features and also trying to tidy up the code and make it more consistent.  The previous developer uses two ways of declaring functions and I can&#...

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What is the difference between using call and apply to invoke a function?  var func = function() {   alert('hello!'); };   func.apply(); vs func.call();  Are there performance differences between the two aforementioned methods? When is it b...

The new es6 arrow functions say return is implicit under some circumstances:     The expression is also the implicit return value of that function.   In what cases do I need to use return with es6 arrow functions?...

We have two different way for doing function expression in JavaScript:  Named function expression (NFE):   var boo = function boo () {   alert(1); };   Anonymous function expression:  var boo = function () {   alert(1); };   And both of them can be...

I have a function callWithMagic which takes a callback function as a parameter and calls it with one argument.  const callWithMagic = callback => {   const magic = getMagic();   callback(magic); };   I also have a function processMagic which tak...

I recently updated jQuery from 1.8 to 2.1. I suddenly discovered that the .live() stops working. I get the error TypeError: $(...).live is not a function.  Is there any method I can use in place of .live()?...

What is the simplest/cleanest way to implement singleton pattern in JavaScript?...

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