Given a JSX expression, expr may either refer to something intrinsic to the environment (e.g. In order to understand type checking with JSX, you must first understand the difference between intrinsic elements and value-based elements. tsx files, and is identical in behavior to the angle-bracket type assertion style. *Note: You can specify the JSX factory function to use when targeting react JSX emit with jsxFactory option (defaults to React.createElement) The as operator You can specify this mode using either the jsx command line flag or the corresponding option jsx in your tsconfig.json file. The react-native mode is the equivalent of preserve in that it keeps all JSX, but the output will instead have a. The react mode will emit React.createElement, does not need to go through a JSX transformation before use, and the output will have a. Babel).Īdditionally the output will have a. The preserve mode will keep the JSX as part of the output to be further consumed by another transform step (e.g. These modes only affect the emit stage - type checking is unaffected. TypeScript ships with three JSX modes: preserve, react, and react-native. In order to use JSX you must do two things.

TypeScript supports embedding, type checking, and compiling JSX directly to JavaScript. JSX rose to popularity with the React framework, but has since seen other implementations as well. (Following the trace, it points to the second line of the following:) var Popup = /*#_PURE_*/(0,react_WEBPACK_IMPORTED_MODULE_0_.It is meant to be transformed into valid JavaScript, though the semantics of that transformation are implementation-specific. The above error occurred in the component: Uncaught TypeError: Cannot read properties of null (reading 'useState') Hooks can only be called inside of the body of a function component. Either way, it brings forth a cascade of error messages, none of which seemed to emanate from within my code: Warning: Invalid hook call. įirst I tried pasting this into my React program and using it as a component: const Modal = () => (įailing that, I tried incorporating his 'Custom modal' example, pasting it into a file and then importing that file as a component. Among others, I've tried working from this page, whose pop-ups operate fine on its own page. I am trying to learn how to use reactjs-popup, and every attempt is failing with similar error messages.

For each reactjs