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Declaring Variables in JavaScript
1:20Let's review the original way to declare a variable and how that differs with the modern let and const keywords.
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>> Hello world, Andrew here.
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Lifelong learner, and
JavaScript teacher here at Treehouse.
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For most of JavaScripts life,
there's been only one way to create or
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declare a variable.
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Using the var keyword.
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Most JavaScript programmers
learned this method, and
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a lot still use the var keyword.
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But some of the behaviors from using
var can be problematic or unexpected.
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That's why developers of
the JavaScript programming language
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decided to introduce new ways for
creating variables.
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The sixth version of JavaScript,
called ES2015, or
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ECMAScript 2015, introduced two
new keywords, const and let.
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In this workshop,
I'll show you how const and let work, and
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explain why you'll want to use them
instead of var when declaring variables.
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But first,
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I just want to mention that const and
let work in a similar way to var.
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In each case you use the keyword var,
const, or
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let, followed by the name of the variable,
an equal sign and
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a value you want to put
into that variable.
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So, when should you use const,
and when should you use let?
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Great questions.
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I'll answer them in the next few videos.
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