Object Orientated Programming

TypeScript vs JavaScript

The examples given are EMCAScript prototype equivalent of create a factory function and adding to the prototype.

It reduces complexity through meaningful signalling of communication.

Feature Complexity

When you programming, what is it that you do?

Object Modelling as Nouns

A major painpoint of complexity is that a person has not properly mapped out the domain model for what they are trying to describe.

You MUST get your domain model correct.

The session talks to objects and how interfaces are "contracts" to describe the object shape.

Methods as Verbs

Object can do things.

We want to describe what a function does.

In this lesson, a Store is defined for the Client object as ClientStore which is a class that hosts methods to work on the clients, and also stores the clients and stores the "current client".

Things to note from the class:

interface Client {
    id: number
    name: string
}

interface ClientState {
  clients: Client[],
  currentClient: Client
}

class ClientStore {
  #state: ClientState

  constructor(state: ClientState) {
    this.#state = state
  }

  getState(): ClientState {
    return this.#state
  }

  select(key: keyof ClientState)  {
    return this.#state[key];
  }
}

const clients: Client[] = [{
    id: 1,
    name: 'Dennis'
}, {
    id: 2,
    name: 'Bob'
}]

const clientState: ClientState = {
    clients,
    currentClient: clients[0]
}

const clientStore = new ClientStore(clientState)
console.log(clientStore.select('currentClient'))
copy

Note: I am using the TS # pound to create "true privacy".