Declarations with let and const

Learning objective

Declare mutable and immutable values correctly.

Key syntax

let total: int = 0;
const pi: float = 3.1416;

Examples

Use let for values that change in loops or state updates.
Use const for fixed values such as config constants.

Common mistakes

Redeclaring a symbol in the same scope.
Reassigning a const variable.

Suggested practice

Refactor a script to replace magic numbers with const values.

types-and-collections
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