The Angular Compiler requires TypeScript >=3.6.4 and <3.9.0 but 3.9.9 was found instead code example
Example: ERROR in The Angular Compiler requires TypeScript >=4.0.0 and <4.1.0 but 3.4.5 was found instead.
npm i -D typescript@4.0.5
npm i -D typescript@4.0.5