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layout: post title: JSX date: 2018-03-12 —

JSX

JSX is an XML/HTML-like syntax used by React that extends ECMAScript so that XML/HTML-like text can co-exist with JavaScript/React code. The syntax is intended to be used by preprocessors (i.e., transpilers like Babel) to transform HTML-like text found in JavaScript files into standard JavaScript objects that a JavaScript engine will parse.

Basically, by using JSX you can write concise HTML/XML-like structures (e.g., DOM like tree structures) in the same file as you write JavaScript code, then Babel will transform these expressions into actual JavaScript code. Unlike the past, instead of putting JavaScript into HTML, JSX allows us to put HTML into JavaScript.

Don’t think of JSX as a template but instead as a special/alternative JS syntax that has to be compiled. I.e., JSX is simply converting XML-like markup into JavaScript.JSX is a separate thing from React itself. JSX does not attempt to comply with any XML or HTML specifications. JSX is designed as an ECMAScript feature and the similarity to XML/HTML is only at the surface.