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Let's review the original way to declare a variable and how that differs with the modern let and const keywords.
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[MUSIC]
0:00
Hello world, Andrew here, lifelong learner
and JavaScript teacher here at Treehouse.
0:04
For most of JavaScript's life,
there's been only one way to create or
0:10
declare a variable, using the var keyword.
0:14
Most JavaScript programmers
learned this method and
0:18
a lot still use the var keyword, but
0:21
some of the behaviors from using var
can be problematic or unexpected.
0:23
That's why developers of
the JavaScript programming language
0:28
decided to introduce new ways for
creating variables.
0:31
The sixth version of
JavaScript called ES 2015 or
0:35
ECMAScript 2015,
introduce two new keywords.
0:40
Const and let.
0:44
In this workshop,
I'll show you how const and let work.
0:46
And explain why you'll want to use them
instead of var, when declaring variables.
0:49
But first,
0:54
I just want to mention that const and
let work in a similar way to var.
0:55
In each case, you use the keyword var,
const, or let.
1:00
Followed by the name of the variable,
an equal sign and
1:05
the value you want to
put into that variable.
1:09
So, when should you use const and
when should you use let?
1:12
Great questions.
1:16
I'll answer them in the next few videos.
1:17
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