[react-markdown] ie11 support

[R-Gopi]

React markdown viewer not working in ie11,how to solve this tried by adding poly fills but no luck

[ChristianMurphy]

React Markdown uses both new syntax features (like const) and new APIs (like Object.assign).
Polyfills work for new APIs, for new syntax a transpiler is needed.
Consider using babel preset env https://babeljs.io/docs/en/babel-preset-env and set it to support your desired browser matrix.

[vijayapalemis]

Already i am using the react-app-polyfill to support the above features, but still i am getting syntax error

[wooorm]

You need to configure the tools you are using

[ChristianMurphy]

i am using the react-app-polyfill to support the above features, but still i am getting syntax error

@vijayapalemis as noted in the original response.
You need both polyfills, and a transpiler. react-app-polyfill is a polyfill but not a transpiler, you still need a traspiler like babel, or an equivalent tool.
If you are using create react app, make sure you are using the latest version of react scripts, and follow the guide on legacy browser support https://create-react-app.dev/docs/supported-browsers-features.
If you have a custom webpack/build system, you'll need to add the transpiler manually.