JSX

A syntax that lets you write HTML-like code inside JavaScript — like writing a letter where English and code live side by side.

A syntactic extension to JavaScript that compiles to React.createElement (or the JSX runtime's jsx function) calls. It allows declarative UI descriptions with embedded expressions, mapped to virtual DOM elements.

JSX is transformed by a compiler (Babel, SWC, or TypeScript) into function calls defined by the JSX runtime. The automatic runtime (react/jsx-runtime) eliminates the need for React in scope. TypeScript's JSX support type-checks element attributes against intrinsic elements (JSX.IntrinsicElements) or component prop types, providing compile-time safety for the template layer.