The Angular Compiler requires TypeScript >=3.9.2 and <4.1.0 but 4.2.3 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