OMI - Web Components Framework

TodoApp with reactivity functions

Data oriented programming

In data-oriented programming, the focus is on the data itself and the operations on the data, rather than the objects or data structures that hold the data. This programming paradigm emphasizes the change and flow of data, and how to respond to these changes. The TodoApp with reactivity functions is a good example of this, using the concepts of reactive programming, where the UI automatically updates to reflect changes in the data (i.e., the to-do list).

tsx

import { render, signal, computed, tag, Component, h } from 'omi'

const todos = signal([
  { text: 'Learn OMI', completed: true },
  { text: 'Learn Web Components', completed: false },
  { text: 'Learn JSX', completed: false },
  { text: 'Learn Signal', completed: false }
])

const completedCount = computed(() => {
  return todos.value.filter(todo => todo.completed).length
})

const newItem = signal('')

function addTodo() {
  todos.value = [...todos.value, { text: newItem.value, completed: false }]
  newItem.value = '' // Reset input value on add
}

function removeTodo(index: number) {
  todos.value.splice(index, 1)
  todos.value = [...todos.value]
}

@tag('todo-list')
class TodoList extends Component {
  onInput = (event: Event) => {
    const target = event.target as HTMLInputElement
    newItem.value = target.value
  }

  render() {
    return (
      <>
        <input type="text" value={newItem.value} onInput={this.onInput} />
        <button onClick={addTodo}>Add</button>
        <ul>
          {todos.value.map((todo, index) => {
            return (
              <li>
                <label>
                  <input
                    type="checkbox"
                    checked={todo.completed}
                    onInput={() => {
                      todo.completed = !todo.completed
                      todos.value = [...todos.value]
                    }}
                  />
                  {todo.completed ? <s>{todo.text}</s> : todo.text}
                </label>
                {' '}
                <button onClick={() => removeTodo(index)}>❌</button>
              </li>
            )
          })}
        </ul>
        <p>Completed count: {completedCount.value}</p>
      </>
    )
  }
}

render(<todo-list />, document.body)

import { render, signal, computed, tag, Component, h } from 'omi'

const todos = signal([
  { text: 'Learn OMI', completed: true },
  { text: 'Learn Web Components', completed: false },
  { text: 'Learn JSX', completed: false },
  { text: 'Learn Signal', completed: false }
])

const completedCount = computed(() => {
  return todos.value.filter(todo => todo.completed).length
})

const newItem = signal('')

function addTodo() {
  todos.value = [...todos.value, { text: newItem.value, completed: false }]
  newItem.value = '' // Reset input value on add
}

function removeTodo(index: number) {
  todos.value.splice(index, 1)
  todos.value = [...todos.value]
}

@tag('todo-list')
class TodoList extends Component {
  onInput = (event: Event) => {
    const target = event.target as HTMLInputElement
    newItem.value = target.value
  }

  render() {
    return (
      <>
        <input type="text" value={newItem.value} onInput={this.onInput} />
        <button onClick={addTodo}>Add</button>
        <ul>
          {todos.value.map((todo, index) => {
            return (
              <li>
                <label>
                  <input
                    type="checkbox"
                    checked={todo.completed}
                    onInput={() => {
                      todo.completed = !todo.completed
                      todos.value = [...todos.value]
                    }}
                  />
                  {todo.completed ? <s>{todo.text}</s> : todo.text}
                </label>
                {' '}
                <button onClick={() => removeTodo(index)}>❌</button>
              </li>
            )
          })}
        </ul>
        <p>Completed count: {completedCount.value}</p>
      </>
    )
  }
}

render(<todo-list />, document.body)

TodoApp with Signal Class

Object oriented programming

In object-oriented programming, the focus is on the objects, which contain both data and methods to operate on the data. This programming paradigm emphasizes the interaction and cooperation between objects, and how to organize and manage code through object encapsulation, inheritance, and polymorphism. The TodoApp with reactivity functions can also be implemented in an object-oriented way, for example, by creating a TodoList class that contains the data of the to-do list and methods to operate on this data, as well as a update method to update the UI.

tsx

import { render, Signal, tag, Component, h, computed } from 'omi'

type Todo = { text: string, completed: boolean }

class TodoApp extends Signal<{ todos: Todo[], filter: string, newItem: string }> {
  completedCount: ReturnType<typeof computed>

  constructor(todos: Todo[] = []) {
    super({ todos, filter: 'all', newItem: '' })
    this.completedCount = computed(() => this.value.todos.filter(todo => todo.completed).length)
  }

  addTodo = () => {
    // api a
    this.value.todos.push({ text: this.value.newItem, completed: false })
    this.value.newItem = ''
    this.update()

    // api b, same as api a
    // this.update((value) => {
    //   value.todos.push({ text: value.newItem, completed: false })
    //   value.newItem = ''
    // })
  }

  toggleTodo = (index: number) => {
    const todo = this.value.todos[index]
    todo.completed = !todo.completed
    this.update()
  }

  removeTodo = (index: number) => {
    this.value.todos.splice(index, 1)
    this.update()
  }
}

const todoApp = new TodoApp([
  { text: 'Learn OMI', completed: true },
  { text: 'Learn Web Components', completed: false },
  { text: 'Learn JSX', completed: false },
  { text: 'Learn Signal', completed: false }
])

@tag('todo-list')
class TodoList extends Component {
  onInput = (event: Event) => {
    const target = event.target as HTMLInputElement
    todoApp.value.newItem = target.value
  }

  render() {
    const { todos } = todoApp.value
    const { completedCount, toggleTodo, addTodo, removeTodo } = todoApp
    return (
      <>
        <input type="text" value={todoApp.value.newItem} onInput={this.onInput} />
        <button onClick={addTodo}>Add</button>
        <ul>
          {todos.map((todo, index) => {
            return (
              <li>
                <label>
                  <input
                    type="checkbox"
                    checked={todo.completed}
                    onInput={() => toggleTodo(index)}
                  />
                  {todo.completed ? <s>{todo.text}</s> : todo.text}
                </label>
                {' '}
                <button onClick={() => removeTodo(index)}>❌</button>
              </li>
            )
          })}
        </ul>
        <p>Completed count: {completedCount.value}</p>
      </>
    )
  }
}

render(<todo-list />, document.body)

import { render, Signal, tag, Component, h, computed } from 'omi'

type Todo = { text: string, completed: boolean }

class TodoApp extends Signal<{ todos: Todo[], filter: string, newItem: string }> {
  completedCount: ReturnType<typeof computed>

  constructor(todos: Todo[] = []) {
    super({ todos, filter: 'all', newItem: '' })
    this.completedCount = computed(() => this.value.todos.filter(todo => todo.completed).length)
  }

  addTodo = () => {
    // api a
    this.value.todos.push({ text: this.value.newItem, completed: false })
    this.value.newItem = ''
    this.update()

    // api b, same as api a
    // this.update((value) => {
    //   value.todos.push({ text: value.newItem, completed: false })
    //   value.newItem = ''
    // })
  }

  toggleTodo = (index: number) => {
    const todo = this.value.todos[index]
    todo.completed = !todo.completed
    this.update()
  }

  removeTodo = (index: number) => {
    this.value.todos.splice(index, 1)
    this.update()
  }
}

const todoApp = new TodoApp([
  { text: 'Learn OMI', completed: true },
  { text: 'Learn Web Components', completed: false },
  { text: 'Learn JSX', completed: false },
  { text: 'Learn Signal', completed: false }
])

@tag('todo-list')
class TodoList extends Component {
  onInput = (event: Event) => {
    const target = event.target as HTMLInputElement
    todoApp.value.newItem = target.value
  }

  render() {
    const { todos } = todoApp.value
    const { completedCount, toggleTodo, addTodo, removeTodo } = todoApp
    return (
      <>
        <input type="text" value={todoApp.value.newItem} onInput={this.onInput} />
        <button onClick={addTodo}>Add</button>
        <ul>
          {todos.map((todo, index) => {
            return (
              <li>
                <label>
                  <input
                    type="checkbox"
                    checked={todo.completed}
                    onInput={() => toggleTodo(index)}
                  />
                  {todo.completed ? <s>{todo.text}</s> : todo.text}
                </label>
                {' '}
                <button onClick={() => removeTodo(index)}>❌</button>
              </li>
            )
          })}
        </ul>
        <p>Completed count: {completedCount.value}</p>
      </>
    )
  }
}

render(<todo-list />, document.body)

We won't discuss which method is good or bad here. You can choose either method using omi.

TodoApp with reactivity functions ​

TodoApp with Signal Class ​

TodoApp with reactivity functions

TodoApp with Signal Class