Understanding Data Types in JavaScript

Data types describe the kind of data stored in a variable. Here are some common data types in JavaScript:

1. Number

Used for numbers, both whole and decimal.

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let score = 100;
let price = 19.99;

2. String

Strings are text wrapped in quotes.

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let greeting = "Hello, world!";
let favoriteColor = 'blue';

3. Boolean

Boolean values are either true or false, perfect for yes/no questions.

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let isSunny = true;
let isNight = false;

4. Null

null represents “no value.” It’s intentional, meaning the variable is empty on purpose.

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let result = null;

5. Undefined

If a variable has been declared but not assigned a value, it is undefined.

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let futureValue;
console.log(futureValue); // Output: undefined