Learning Redux

Defining the run method

Next, we define the run method, which takes a function as an argument. This function will be called after the middleware function finishes running:

1. Define the run method:

  run (fn) {

2. In this function, we call this.middleware() and pass a next function to it:

    this.middleware(

3. The next function will end up calling the passed function, fn, with the this context of our library:

      () => fn.call(this)    )  }

Every non-arrow function (this includes the function and class definitions) has its own this context. Arrow functions, however, can access the this context from the upper scope, meaning that they inherit the this context from the parent scope (defined by { } brackets).

Up to now, we have not dealt with this context ...