build-sidebar has error #299

Building _sidebar.md
(node:2984) UnhandledPromiseRejectionWarning: TypeError: fs.opendirSync is not a function
    at getFiles (C:\Users\javad\Documents\public_html\Scripts\Learn-JavaScript\scripts\build-sidebar.js:7:18)
    at buildSection (C:\Users\javad\Documents\public_html\Scripts\Learn-JavaScript\scripts\build-sidebar.js:21:23)
    at buildSidebar (C:\Users\javad\Documents\public_html\Scripts\Learn-JavaScript\scripts\build-sidebar.js:36:25)
    at Object.<anonymous> (C:\Users\javad\Documents\public_html\Scripts\Learn-JavaScript\scripts\build-sidebar.js:44:1)
    at Module._compile (internal/modules/cjs/loader.js:936:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:947:10)
    at Module.load (internal/modules/cjs/loader.js:790:32)
    at Function.Module._load (internal/modules/cjs/loader.js:703:12)
    at Function.Module.runMain (internal/modules/cjs/loader.js:999:10)
    at internal/main/run_main_module.js:17:11
(node:2984) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). (rejection id: 2)
(node:2984) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.