Cannot find namespace 'ctx' error when creating Context with react - typescript

I'm working on a project with react using typescript and I'm having a bad time figuring out why this error is happening, basically, I can't use any createContext examples that I found on the internet because of this.
This one specifically I got from here: https://github.com/typescript-cheatsheets/react-typescript-cheatsheet I'm trying to use the same that is showing in the Context section.

import * as React from "react";

export function createCtx(defaultValue: A) {
type UpdateType = React.Dispatch>;
const defaultUpdate: UpdateType = () => defaultValue;
const ctx = React.createContext({
    state: defaultValue,
    update: defaultUpdate
});
function Provider(props: React.PropsWithChildren) {
    const [state, update] = React.useState(defaultValue);
    return ;
}
return [ctx, Provider] as [typeof ctx, typeof Provider];
}

The issue is that everytime it says that there's this error
Cannot find namespace ctx in the line:

return ;

I'm still not able to figure out why, someone can see if I'm doing something wrong here? This is my tsconfig.json:

{
"compilerOptions": {
"target": "es5",
"lib": [
  "dom",
  "dom.iterable",
  "esnext"
],
"allowJs": true,
"skipLibCheck": true,
"esModuleInterop": true,
"allowSyntheticDefaultImports": true,
"strict": false,
"forceConsistentCasingInFileNames": true,
"module": "esnext",
"moduleResolution": "node",
"resolveJsonModule": true,
"isolatedModules": true,
"noEmit": true,
"jsx": "preserve",
"noImplicitAny": false,
"strictNullChecks": false
},
"include": [
"src"
]
}

Any help would be appreciated!

Your file extension is most likely .ts instead of .tsx.

Therefore TypeScript is interpreting <ctx.Provider as cast and tries to find a type Provider in the namespace ctx.

Stack Overflow Q#57242264, score: 716