Lecture

Constant Declaration Keyword, const

const is short for Constant, which means that once a value has been set, it cannot be changed.

Therefore, a variable declared using const cannot have its value altered once it is assigned.

Declaring a constant with const
const birthYear = 1995;

In the example above, the constant birthYear is assigned the numeric value 1995.

Since birthYear is declared with const, its value cannot be changed once set.

The scope of a const declared variable, like let, is block-level scope.

Thus, a variable declared with const inside curly braces is not accessible outside that code block.


Why Use const as a Constant Variable?

  • To Store Values That Should Not Change: It is used when you want to safely store values that should not change once set, such as a website's default color or a user's birth year.

  • Improving Code Stability: By using const, you prevent the value from being accidentally modified. This helps to reduce errors in your program, making it more robust.

Mission
0 / 1

A constant declared with const can have its value changed.

True
False

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