JavaScript(JS) Expressions

In JavaScript, an expression is a piece of code that produces a value. This value can be a primitive value (like a number or a string) or an object. Expressions are used to perform calculations, assign values to variables, and evaluate conditions, among other things.

Here are some examples of JavaScript expressions:

3 + 4 // Produces the value 7
"Hello, " + "world!" // Produces the value "Hello, world!"
true && false // Produces the value false
(4 * 5) + 2 // Produces the value 22

In these examples, the expressions are evaluated and produce a value that can be assigned to a variable or used in other expressions.

Expressions can also contain variables, which are placeholders for values that can change over time. Here is an example:

let x = 5;
let y = x + 3; // The expression "x + 3" produces the value 8

In this example, the variable x is assigned the value 5, and the variable y is assigned the value 8, which is produced by the expression x + 3.

Expressions can also contain function calls. Here is an example:

function square(x) {
  return x * x;
}

let result = square(4) + square(3); // The expression "square(4) + square(3)" produces the value 25

In this example, the function square is called with the arguments 4 and 3, and the expression square(4) + square(3) produces the value 25, which is assigned to the variable result.