WEBVTT

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Hi and welcome to this
video course on JavaScript.

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Let's take a closer look at common

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misunderstandings about
objects and arrays.

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It's important to understand the concept

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of primitive and reference
types in JavaScript.

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As a reminder, objects
and arrays are reference types.

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This means that even if you store an array
in a constant,

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you can still edit the array without
breaking the constant restriction.

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To demonstrate this

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let's take the following example.

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Let's create an array that's a constant -hobbies

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and let's write reading
and cooking inside this array.

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Now let's say we want to push a new

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element to the existing
array using the push method.

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So let's do hobbies push programming.

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Now if we console log
hobbies, the output will be reading,

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cooking and programming and there will be
no error about editing a constant value.

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This is because reference types only store

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an address pointing to the memory
location where the array is stored.

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When we add a new element,
this address remains unchanged

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and the constant still points
to the same location in memory.

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It's important to understand this so

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that you don't get confused
when editing a constant value.

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We're not actually editing the constant
value, but the value it's pointing to.

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So same happens with the object.

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So let's create hobbies object

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and let's say that this is Nata's
hobby and type is programming.

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If we want to add to hobbies object

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a value of age for example,
and we output the hobbies object,

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we're going to see age appear here
because objects are also reference types.

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However, if you create number for example,

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and USA is twelve,
which is a primitive type,

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and now you want to reassign number
to 13 and we console log number.

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If we run this,
we're going to get an error saying

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that we're trying to assign something
else to our constant variables.

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So that's all for this video.

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Thanks for watching and see
you in the next one.