UnSub

This package provides a compatibility layer to ReSub making it viable to code written in CoffeeScript.

Installation

npm install unsub resub

Usage

## TodosStore.coffee
import { StoreBase, AutoSubscribeStore } from "unsub"

export default new TodosStore = AutoSubscribeStore class extends StoreBase
  @Key_SomeFilter = "Key_SomeFilter"

  @autoSubscribeWithKey @Key_SomeFilter, getTodos: ->
    @_todosFiltered

  @autoSubscribe @key getTodosForUser: (username) ->
    @_todosByUser[username]

## TodoList.coffee
import { ComponentBase } from "unsub"
import TodosStore from "./TodosStore"

export class TodoList extends ComponentBase
  buildState: (props, state, bInit) ->
    todosFiltered: TodosStoreInstance.getTodos()
    userTodos: TodosStoreInstance.getTodosForUser @props.username

  render: ->
    <div>
    { @state.userTodos.map (todo) ->
      <Todo key={todo.id}>
        {todo.text}
      </Todo>
    }
    </div>

Above code is equivalent to this TypeScript code:

/// TodosStore.ts
import { StoreBase, AutoSubscribeStore, autoSubscribe, key } from 'resub';

@AutoSubscribeStore
class TodosStore extends StoreBase {
    static Key_SomeFilter = "Key_SomeFilter";

    @autoSubscribeWithKey(TodosStore.Key_SomeFilter)
    getTodos() {
        return this._todosFiltered;
    }

    @autoSubscribe
    getTodosForUser(@key username: string) {
        return this._todosByUser[username];
    }
}

export = new TodosStore();

/// TodoList.tsx
import { ComponentBase } from 'resub';
import TodosStore from './TodosStore';

export class TodoList extends ComponentBase<{}, TodoListState> {
    protected _buildState(props: {}, initialBuild: boolean, state: {}): TodoListState {
        return {
            todosFiltered: TodosStoreInstance.getTodos(),
            userTodos: TodosStoreInstance.getTodosForUser(this.props.username)
        }
    }

    render() {
      return (
          <div>
          { this.state.userTodos.map( todo => (
              <Todo key={ todo.id }>
                  { todo.text }
              </Todo>
          ))}
          </div>
      );
    }
}

Breaking Change in v2.0.0

ReSub v2.0.0-rc.2 introduced a new argument to stores' _buildState function.

# old:
buildState: (props, bInit) ->
_buildState: (props, bInit) ->
# new:
buildState: (props, state, bInit) ->
_buildState: (props, bInit, state) ->

Reasoning for the new argument:

Changes in ReSub/React made it unreliable and bugprone to use this.state inside _buildState. It was not always updated and would reflect old state. As a workaround they added state as a third argument.

Reasoning for breaking the old signature:

There's 2 parts to that answer.

Firstly it feels far more natural to have state follow props. Most (if not all these days) of React's functions taking both props and state have them as the first 2 arguments and in that same order; especially if you use preact (which you should).

Secondly, if you made use of @state inside buildState there's a high chance it's buggy now (breaking change in React/ReSub). To fix that you are required to go thru your code and switch to using the state argument. While doing that you may as well switch to the new (and better) signature.

Yes, if you aren't affected by #2 bInit still moved and I broke your components. The above 2 reasons are big enough to warrant you do a search and replace.

Overview

UnSub principially is used the same way as ReSub. One key difference is that decorators which take an argument do not return a decorator when called but instead are called with the arguments, followed by whatever they are decorating.

# correct:
@autoSubscribeWithKey @Key_Filtered, getFilteredData: -> @filteredData
# incorrect:
@autoSubscribeWithKey(@Key_Filtered) getFilteredData: -> @filteredData

Furthermore it allows you to omit the underscore on your overrides. E.g. buildState instead of _buildState. This more closely follows React's style of writing components.

Also see v2's breaking changes in the previous section.

Exports

Classes

• StoreBase
• ComponentBase

Class Decorators

• AutoSubscribeStore
• DeepEqualityShouldComponentUpdate
• CustomEqualityShouldComponentUpdate COMPARE

MyStore = CustomEqualityShouldComponentUpdate shouldComponentUpdateCb, class extends StoreBase
  getData: -> @data

Member Function Decorators

• @autoSubscribe
• @autoSubscribeWithKey KEY
• @disableWarnings
  Native to ReSub, undocumented.
• @bound
  Helper which binds the function in the constructor.
  This is necessary because fat arrows would bind to the constructor/class.

Parameter Decorators

• @key [INDEX]
  Used outside parameter list. Index represents arguments[index], is optional and defaults to 0.

MyStore = AutoSubscribeStore class extends StoreBase
  @autoSubscribe @key 1, @bound getData: (a, b) ->
     # `b` is the key ^
    @data[b][a]

Note that member function and parameter decorators (prefixed with @) are actually static class members of StoreBase. This means that you must not have static members on your store that use the same identifier as a decorator you make use of inside the class body. It also means that you only need to import classes and class decorators.

For more information please refer to the ReSub documentation.