GenerateClassMock

With this library you can use generateClassMock method to generate ES6 class mock.

This function returns new class with same attributes as the original one and all methods replaced with () => {}.

Usage

generateClassMock takes 2 parameters:

• first, a class which needs to be mocked
• second, options cfg object

Cfg object

Cfg object can have any of the following attributes:

• prototypes If there is a need for a method to be anything else than () => {} you can provide it as following:

  {
    prototypes: {
      methodName: () => 5 (or other value)
    }
  }

• attributes If there is a need for a attribute to have custom value, you can provide it as following:

  {
    attributes: {
      attributeName: 5 (or other value)
    }
  }

• replaceOriginalPrototype Due to internal mechanisms of generateClassMock function in case there is a logic in constructor that uses constructor attributes there is a need to move all that logic to separate function and add its name to cfg replaceOriginalPrototype array.

  {
    replaceOriginalPrototype: ['fnName']
  }

replaceOriginalPrototype - usage example

Instead of:

class ClassToMock {
  constructor(private attr1) {
    this.attr1.someFn();
  }
}

Do:

class ClassToMock {
  constructor(private attr1) {
    this.constructorLogic();
  }
  
  private constructorLogic() {
    this.attr1.someFn();
  }
}

and mock it with cfg:

{
  replaceOriginalPrototype: ['constructorLogic']
}