jest

What is declarative programming? It means to specify (declare) what to do without the how.A more in-depth explanation is available on wikipedia. Context I have always found it easier to explain concepts using examples.Suppose, we have a config class that reads and validates environment variables so that they can be used in some parts of the application. Below is an example of such a config class.Not-relevant code, such as the validation code and methods, have been removed. export class AWSConfig { readonly accessKeyID: string; readonly secretAccessKey: string; readonly region: string; constructor() { // ... code to validate environment variables //…