TypeScript - TypeError: fs.existsSync is not a function

I am new to typescript and React, I am trying to load all files in array,

    const path = require('path');    const fs = require('fs');    const directoryPath = path.join("/checking/");    if (!fs.existsSync(directoryPath)) {        console.log('good')    }

This shows error in Browser Console-

    Uncaught TypeError: fs.existsSync is not a function        at startEditor1 (main.chunk.js:25202)        at onClick (main.chunk.js:25377)        at onClickHandler (main.chunk.js:16866)        at HTMLUnknownElement.callCallback (vendors~main.chunk.js:140757)        at Object.invokeGuardedCallbackDev (vendors~main.chunk.js:140806)        at invokeGuardedCallback (vendors~main.chunk.js:140860)        at invokeGuardedCallbackAndCatchFirstError (vendors~main.chunk.js:140875)        at executeDispatch (vendors~main.chunk.js:141181)        at executeDispatchesInOrder (vendors~main.chunk.js:141206)        at executeDispatchesAndRelease (vendors~main.chunk.js:141305)        at executeDispatchesAndReleaseTopLevel (vendors~main.chunk.js:141314)        at forEachAccumulated (vendors~main.chunk.js:141286)        at runEventsInBatch (vendors~main.chunk.js:141454)        at runExtractedEventsInBatch (vendors~main.chunk.js:141462)        at handleTopLevel (vendors~main.chunk.js:145639)        at batchedUpdates$1 (vendors~main.chunk.js:162073)        at batchedUpdates (vendors~main.chunk.js:142857)        at dispatchEvent (vendors~main.chunk.js:145719)        at vendors~main.chunk.js:162130        at Object.unstable_runWithPriority (vendors~main.chunk.js:179596)        at interactiveUpdates$1 (vendors~main.chunk.js:162129)        at interactiveUpdates (vendors~main.chunk.js:142878)        at dispatchInteractiveEvent (vendors~main.chunk.js:145695)

How to solve this error, thanks