Var vs let in javascript
Scoping rulesThe main difference is scoping rules. Variables declared by Show
The reason why Take a look at this example from another Stack Overflow question:
People had to create immediately invoked functions to capture correct values from the loops but that was also hairy. HoistingWhile variables declared with
Creating global object propertyAt the top level,
RedeclarationIn strict mode,
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Code above demonstrates a classic JavaScript closure problem. Reference to the Every single click handler will refer to the same object because there’s only one counter object which holds 6 so you get six on each click. A general workaround is to wrap this in an anonymous function and pass (Tested in Chrome and Firefox 50)
answered May 27, 2015 at 10:16
Gurpreet SinghGurpreet Singh 20.4k5 gold badges42 silver badges57 bronze badges 13 What's the difference between let and var?
To understand the difference, consider the following code:
Here, we can see that our variable Also, consider that block scoped variables are not known before they are declared because they are not hoisted. You're also not allowed to redeclare the same block scoped variable within the same block. This makes block scoped variables less error prone than globally or functionally scoped variables, which are hoisted and which do not produce any errors in case of multiple declarations. Is it safe to use let today?Some people would argue that in the future we'll ONLY use let statements and that var statements will become obsolete. JavaScript guru Kyle Simpson wrote a very elaborate article on why he believes that won't be the case. Today, however, that is definitely not the case. In fact, we need actually to ask ourselves whether it's safe to use the
How to keep track of browser supportFor an up-to-date overview of which browsers support the (*) Globally and functionally scoped variables can be initialized and used before they are declared because JavaScript variables are hoisted. This means that declarations are always much to the top of the scope. (**) Block scoped variables are not hoisted answered Feb 23, 2016 at 18:35
John SlegersJohn Slegers 42.6k22 gold badges194 silver badges162 bronze badges 6 Here's an explanation of the
This table on Wikipedia shows which browsers support Javascript 1.7. Note that only Mozilla and Chrome browsers support it. IE, Safari, and potentially others don't.
answered Apr 17, 2009 at 20:11
Ben SBen S 67.5k30 gold badges170 silver badges212 bronze badges 5 The accepted answer is missing a point:
William 4039 silver badges21 bronze badges answered Jun 2, 2015 at 20:59
Lcf.vsLcf.vs 1,7621 gold badge11 silver badges15 bronze badges 4
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