JavaScript, + operator as concatenation operator

In JavaScript, the + operator serves two purposes: addition and string concatenation. Whether it acts as addition or concatenation depends on the operands involved. Here are the general rules:

String Concatenation:

If either operand is a string, JavaScript will treat the + operator as string concatenation. This means it will convert the other operand to a string (if it's not already a string) and then concatenate the two strings.

Example:

let result = "Hello" + " " + "World";  // "Hello World"
let result2 = "Age: " + 25;  // "Age: 25"

Numeric Addition:

If both operands are numbers (or can be coerced to numbers), JavaScript will treat the + operator as numeric addition.

Example:

let result = 5 + 10;  // 15
let result2 = "5" + 10;  // "510" (string concatenation, since one operand is a string)

Type Coercion:

If one operand is a string and the other is a number, the number is automatically converted to a string, and the + operator performs string concatenation instead of numeric addition.

Example:

let result = 5 + " apples";  // "5 apples"

Summary:

• + is used for addition when both operands are numbers (or can be coerced to numbers).
• + is used for concatenation when one or both operands are strings.