Javascript通过单击表头对HTML表进行排序

￡神魔★判官ぃ 2023-09-30 12:08 38阅读 0赞

假设我们要对下表的任何列进行排序：

#### 对行进行排序 ####

首先，我们[查询][Link 1]所有的标头，[遍历][Link 2]它们并为每个标头[附加一个事件处理][Link 3]程序`click`：

// Query the table
    const table = document.getElementById('sortMe');
    
    // Query the headers
    const headers = table.querySelectorAll('th');
    
    // Loop over the headers
    [].forEach.call(headers, function (header, index) {
        header.addEventListener('click', function () {
            // This function will sort the column
            sortColumn(index);
        });
    });

上面提到的`sortColumn(index)`函数将按给定的列对所有行进行排序`index`。为此：

*  我们可以使用`Array`'`sort()`方法对当前行进行排序
 *  然后，[删除][Link 4]所有当前行
 *  并[附加][Link 5]已排序的行

// Query all rows
    const tableBody = table.querySelector('tbody');
    const rows = tableBody.querySelectorAll('tr');
    
    const sortColumn = function (index) {
        // Clone the rows
        const newRows = Array.from(rows);
    
        // Sort rows by the content of cells
        newRows.sort(function (rowA, rowB) {
            // Get the content of cells
            const cellA = rowA.querySelectorAll('td')[index].innerHTML;
            const cellB = rowB.querySelectorAll('td')[index].innerHTML;
    
            switch (true) {
                case cellA > cellB:
                    return 1;
                case cellA < cellB:
                    return -1;
                case cellA === cellB:
                    return 0;
            }
        });
    
        // Remove old rows
        [].forEach.call(rows, function (row) {
            tableBody.removeChild(row);
        });
    
        // Append new row
        newRows.forEach(function (newRow) {
            tableBody.appendChild(newRow);
        });
    };

如您所见，数组提供了一个内置`sort`方法，该方法接受一个函数来比较两个项目。在我们的例子中，列的两个单元格根据其[HTML 内容][HTML]进行比较：

newRows.sort(function(rowA, rowB) {
        // Get the content of cells
        const cellA = rowA.querySelectorAll('td')[index].innerHTML;
        const cellB = rowB.querySelectorAll('td')[index].innerHTML;
    
        ...
    });

它适用于内容为字符串而不是数字或其他类型（如日期）的单元格。转到下一部分，看看我们如何支持这些案例。

#### 支持其他类型 ####

我们为每个标题添加一个自定义属性以指示其单元格的类型：

<thead>
        <tr>
            <th data-type="number">No.</th>
            <th>First name</th>
            <th>Last name</th>
        </tr>
    </thead>

例如，*编号*列将具有一个`data-type="number"`属性。如果缺少该属性，则单元格的内容类型为字符串。我们需要一个函数将单元格的内容从字符串转换为另一种类型：

// Transform the content of given cell in given column
    const transform = function (index, content) {
        // Get the data type of column
        const type = headers[index].getAttribute('data-type');
        switch (type) {
            case 'number':
                return parseFloat(content);
            case 'string':
            default:
                return content;
        }
    };

示例代码演示了`number`和`string`列，但您可以自由支持更多类型，例如日期。

现在我们`sortColumn`稍微改进一下功能以支持自定义内容类型。我们不比较原始内容，而是比较基于内容类型转换的值：

newRows.sort(function (rowA, rowB) {
        const cellA = rowA.querySelectorAll('td')[index].innerHTML;
        const cellB = rowB.querySelectorAll('td')[index].innerHTML;
    
        // Transform the content of cells
        const a = transform(index, cellA);
        const b = transform(index, cellB);
    
        // And compare them
        switch (true) {
            case a > b:
                return 1;
            case a < b:
                return -1;
            case a === b:
                return 0;
        }
    });

#### 支持双向 ####

目前，单击标题会对所有行进行排序。如果用户再次单击标题，我们应该反转方向。为此，我们准备了一个变量来管理所有标题的排序方向：

// Track sort directions
    const directions = Array.from(headers).map(function (header) {
        return '';
    });

`directions`是一个数组，其中每个项目可以是`asc`或`desc`指示关联列中的排序方向。该`sortColumn()`函数现在涉及更多逻辑来根据当前方向比较两行：

#### 演示 ####

通过单击表头对表进行排序

<html lang="en">
        <head>
            <meta charset="utf-8" />
            <title>HTML DOM - Sort a table by clicking its headers</title>
            <meta name="viewport" content="width=device-width, initial-scale=1" />
            <link rel="stylesheet" href="/css/demo.css" />
            <link rel="preconnect" href="https://fonts.gstatic.com" />
            <link
                rel="stylesheet"
                href="https://fonts.googleapis.com/css2?family=Inter&family=Source+Code+Pro&display=swap"
            />
            <style>
                .table {
                    border-collapse: collapse;
                }
                .table__header {
                    background-color: transparent;
                    border: none;
                    cursor: pointer;
                }
                .table,
                .table th,
                .table td {
                    border: 1px solid #ccc;
                }
                .table th,
                .table td {
                    padding: 0.5rem;
                }
                .table th {
                    cursor: pointer;
                    text-decoration: underline;
                }
            </style>
        </head>
        <body>
            <table id="sortMe" class="table">
                <thead>
                    <tr>
                        <th data-type="number"><button class="table__header">No.</button></th>
                        <th><button class="table__header">First name</button></th>
                        <th><button class="table__header">Last name</button></th>
                    </tr>
                </thead>
                <tbody>
                    <tr>
                        <td>1</td>
                        <td>Andrea</td>
                        <td>Ross</td>
                    </tr>
                    <tr>
                        <td>2</td>
                        <td>Penelope</td>
                        <td>Mills</td>
                    </tr>
                    <tr>
                        <td>3</td>
                        <td>Sarah</td>
                        <td>Grant</td>
                    </tr>
                    <tr>
                        <td>4</td>
                        <td>Vanessa</td>
                        <td>Roberts</td>
                    </tr>
                    <tr>
                        <td>5</td>
                        <td>Oliver</td>
                        <td>Alsop</td>
                    </tr>
                    <tr>
                        <td>6</td>
                        <td>Jennifer</td>
                        <td>Forsyth</td>
                    </tr>
                    <tr>
                        <td>7</td>
                        <td>Michelle</td>
                        <td>King</td>
                    </tr>
                    <tr>
                        <td>8</td>
                        <td>Steven</td>
                        <td>Kelly</td>
                    </tr>
                    <tr>
                        <td>9</td>
                        <td>Julian</td>
                        <td>Ferguson</td>
                    </tr>
                    <tr>
                        <td>10</td>
                        <td>Chloe</td>
                        <td>Ince</td>
                    </tr>
                </tbody>
            </table>
    
            <script>
                document.addEventListener('DOMContentLoaded', function () {
                    const table = document.getElementById('sortMe');
                    const headers = table.querySelectorAll('th');
                    const tableBody = table.querySelector('tbody');
                    const rows = tableBody.querySelectorAll('tr');
    
                    // Track sort directions
                    const directions = Array.from(headers).map(function (header) {
                        return '';
                    });
    
                    // Transform the content of given cell in given column
                    const transform = function (index, content) {
                        // Get the data type of column
                        const type = headers[index].getAttribute('data-type');
                        switch (type) {
                            case 'number':
                                return parseFloat(content);
                            case 'string':
                            default:
                                return content;
                        }
                    };
    
                    const sortColumn = function (index) {
                        // Get the current direction
                        const direction = directions[index] || 'asc';
    
                        // A factor based on the direction
                        const multiplier = direction === 'asc' ? 1 : -1;
    
                        const newRows = Array.from(rows);
    
                        newRows.sort(function (rowA, rowB) {
                            const cellA = rowA.querySelectorAll('td')[index].innerHTML;
                            const cellB = rowB.querySelectorAll('td')[index].innerHTML;
    
                            const a = transform(index, cellA);
                            const b = transform(index, cellB);
    
                            switch (true) {
                                case a > b:
                                    return 1 * multiplier;
                                case a < b:
                                    return -1 * multiplier;
                                case a === b:
                                    return 0;
                            }
                        });
    
                        // Remove old rows
                        [].forEach.call(rows, function (row) {
                            tableBody.removeChild(row);
                        });
    
                        // Reverse the direction
                        directions[index] = direction === 'asc' ? 'desc' : 'asc';
    
                        // Append new row
                        newRows.forEach(function (newRow) {
                            tableBody.appendChild(newRow);
                        });
                    };
    
                    [].forEach.call(headers, function (header, index) {
                        header.addEventListener('click', function () {
                            sortColumn(index);
                        });
                    });
                });
            </script>
        </body>
    </html>

![watermark_type_d3F5LXplbmhlaQ_shadow_50_text_Q1NETiBAYWxsd2F5Mg_size_20_color_FFFFFF_t_70_g_se_x_16][]

#### 也可以看看 ####

*  [附加到元素][Link 5]
 *  [附加或分离事件处理程序][Link 3]
 *  [获取或设置元素的html][HTML]
 *  [获取设置和删除数据属性][Link 6]
 *  [循环一个节点列表][Link 2]
 *  [移除一个元素][Link 4]
 *  [选择一个元素或元素列表][Link 1]

[Link 1]: https://htmldom.dev/select-an-element-or-list-of-elements/
[Link 2]: https://htmldom.dev/loop-over-a-nodelist/
[Link 3]: https://htmldom.dev/attach-or-detach-an-event-handler/
[Link 4]: https://htmldom.dev/remove-an-element/
[Link 5]: https://htmldom.dev/append-to-an-element/
[HTML]: https://htmldom.dev/get-or-set-the-html-of-an-element/
[watermark_type_d3F5LXplbmhlaQ_shadow_50_text_Q1NETiBAYWxsd2F5Mg_size_20_color_FFFFFF_t_70_g_se_x_16]: https://img-blog.csdnimg.cn/66d1d323f85b45ddb5368060e9837da7.png?x-oss-process=image/watermark,type_d3F5LXplbmhlaQ,shadow_50,text_Q1NETiBAYWxsd2F5Mg==,size_20,color_FFFFFF,t_70,g_se,x_16
[Link 6]: https://htmldom.dev/get-set-and-remove-data-attributes/