由于某种原因，使用过滤器过滤对象数组不起作用答案

【问题标题】：filtering an object-array with filter doesn't work for some reason由于某种原因，使用过滤器过滤对象数组不起作用
【发布时间】：2019-09-25 20:48:33
【问题描述】：

大家好，我制作了一个 todo 应用程序，它接受用户的输入并将它们制作成 todos，我还添加了一个过滤框，但由于某种原因它似乎不起作用（它在拆分代码之前曾经工作过进入函数调用和基本代码，所以我要把整个代码放在这里，我希望你理解代码。编辑：过滤返回包含过滤输入框中文本的待办事项。

函数调用部分：

//Read and parse existing data in local storage
const getSavedTodos = function() {
    const todoJSON = localStorage.getItem('todo');

    if (todoJSON !== null) {
    return JSON.parse(todoJSON)
    } else {
        return []
    }
}

// save the todos in locale storage
const saveTodos = function(todos) {
    localStorage.setItem('todo', JSON.stringify(todos))
}

// Render todos 
let renderTodos = function(todo, filters) {
    let filteredTodo = todo.filter(function(todo){
        return todo.text.toLowerCase().includes(filters.text.toLowerCase());
    })

    filteredTodo = todos.filter(function(todo){
        return !filters.hideCompleted || !todo.completed;
    })

    document.querySelector('#todo').innerHTML = '';

    const incompleteTodos = filteredTodo.filter(function (todos) {
        return !todos.completed
    })


    const summary = document.createElement('h2')
    summary.textContent = `You have ${incompleteTodos.length} todos left`
    document.querySelector('#todo').appendChild(summary)

    filteredTodo.forEach(function(todo){
        let p = document.createElement('p');
        p.textContent = todo.text;
        document.querySelector('#todo').appendChild(p);
    })
}

基本代码部分：

let todos = getSavedTodos();



let filters = {
    text: '',
    hideCompleted: false
}

renderTodos(todos, filters);

document.querySelector('#filter').addEventListener('input', function(e){
    filters.text = e.target.value.toLowerCase();
    renderTodos(todos, filters);
})

document.querySelector('#form').addEventListener('submit', function(e){
    e.preventDefault();
    todos.push({
        text: e.target.elements.firstName.value,
        completed: false
    })
    saveTodos(todos);
    renderTodos(todos, filters);
    e.target.elements.firstName.value = '';
})

document.querySelector('#hide-completed').addEventListener('change', function(e){
   filters.hideCompleted = e.target.checked;
   renderTodos(todos, filters);
})

HTML 部分：

<header class="header">
      <h1>Todos application</h1>  
    </header>

    <input type="text" id="filter" placeholder="filter the todos">
    <label class="checkbox">
            <input type="checkbox" id="hide-completed">
            <span>hide completed todos</span>
    </label>
    <div id="todo"></div>
    <hr>
    <form id="form">
        Add a new todo:
        <input type="text" placeholder="Type your first name" name="firstName" class="inpt">
        <input type="submit" value="submit" class="btn">
    </form>

    <script src="refraction.js"></script>
    <script src="todo-app.js"></script>

【问题讨论】：

标签： javascript arrays object filter

【解决方案1】：

改变

filteredTodo = todos.filter(function(todo){
    return !filters.hideCompleted || !todo.completed;
})

到

filteredTodo = filteredTodo.filter(function(todo){
    return !filters.hideCompleted || !todo.completed;
})

否则你会废弃原来的过滤。

【讨论】：