In JavaScript, variables and identifiers are related concepts but have distinct meanings:
1. Identifier:
- An identifier is a name given to a variable, function, class, or any other construct in your JavaScript
code.
- It's a way to label and reference values or entities in your code.
- Identifiers follow certain naming rules in JavaScript:
- They must start with a letter (a-z, A-Z), underscore (_), or dollar sign ($).
- Subsequent characters can include letters, digits (0-9), underscores, or dollar signs.
- Identifiers are case-sensitive, meaning `myVariable` and `myvariable` are considered different
identifiers.
Examples of identifiers:
let age; // "age" is an identifier for a variable.
function calculateSum() {} // "calculateSum" is an identifier for a function
class Person {} // "Person" is an identifier for a class
```
2. Variable:
- A variable is a storage location in memory that holds a value or a reference to a value.
- Variables are created using the `var`, `let`, or `const` keyword in JavaScript.
- Variables are identified by their names (identifiers), which allow you to store and manipulate data
within your program.
- Variables can change (hence the name "variable"), and their values can be reassigned during the
execution of your code.
Examples of variables:
let count = 5; // "count" is the variable identifier, and it holds the value 5
const pi = 3.14; // "pi" is the variable identifier, and it holds the value 3.14 (const variables cannot be
reassigned)
In summary, an identifier is the name you give to a variable (or other constructs like functions or classes)
in JavaScript, while a variable is a specific instance that stores data and is referenced by its identifier.
Identifiers follow naming rules, while variables hold values and can be manipulated.