An Introduction to JavaScript Expressions

Expressions are code that evaluates to a value in JavaScript. Primary expressions like number literals are the simplest form, while complex expressions can include operators and function calls. The grouping operator (parentheses) controls evaluation order and disambiguates syntax. Expressions can have side effects beyond their return values, such as variable assignments and function calls. The comma operator evaluates multiple expressions sequentially, discarding intermediate values. Understanding expressions is fundamental to how JavaScript interprets and executes code.