Autocomplete.js是什么？它如何在前端开发中发挥作用？

autocomplete.js：自动完成功能的JavaScript库

autocomplete.js 是一个用于实现输入框自动完成功能的JavaScript库，它通过监听用户的输入事件，动态地显示一个下拉菜单，其中包含与用户输入匹配的选项，这个库广泛应用于各种表单输入场景，如搜索框、地址输入、标签选择等，以提高用户体验和输入效率。

主要功能

1、自动完成：根据用户输入实时显示匹配的选项。

2、自定义数据源：支持从数组、函数或API获取数据源。

3、自定义渲染：允许自定义每个选项的HTML结构。

4、过滤和排序：支持对数据进行过滤和排序。

5、键盘导航：支持使用键盘上下键导航选项，回车键选择选项。

6、多语言支持：内置多种语言支持，方便国际化。

7、可扩展性：可以通过插件机制扩展功能。

安装与引入

通过CDN引入

<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/autocomplete.js@latest/dist/css/autocomplete.min.css">
<script src="https://cdn.jsdelivr.net/npm/autocomplete.js@latest/dist/js/autocomplete.min.js"></script>

通过npm安装

npm install autocomplete.js

在项目中引入：

import 'autocomplete.js/dist/css/autocomplete.min.css';
import Autocomplete from 'autocomplete.js';

基本用法

HTML部分

<input id="my-input" type="text" placeholder="Type something...">

JavaScript部分

const data = ['apple', 'banana', 'grape', 'orange', 'peach'];
new Autocomplete({
  selector: '#my-input',
  minChars: 1,
  source: function(term, suggest){
    const termLower = term.toLowerCase();
    const filtered = data.filter(function(item){
      return item.toLowerCase().indexOf(termLower) > -1;
    });
    suggest(filtered);
  },
  onSelect: function(event, suggestion){
    alert('You selected: ' + suggestion.value);
  }
});

配置项详解

高级用法

自定义数据源

可以通过异步请求获取数据源：

new Autocomplete({
  selector: '#my-input',
  minChars: 1,
  source: function(term, suggest){
    // 模拟异步请求
    setTimeout(function(){
      const termLower = term.toLowerCase();
      const filtered = data.filter(function(item){
        return item.toLowerCase().indexOf(termLower) > -1;
      });
      suggest(filtered);
    }, 500);
  },
  onSelect: function(event, suggestion){
    alert('You selected: ' + suggestion.value);
  }
});

自定义渲染

可以自定义每个选项的HTML结构：

new Autocomplete({
  selector: '#my-input',
  minChars: 1,
  source: function(term, suggest){
    const termLower = term.toLowerCase();
    const filtered = data.filter(function(item){
      return item.toLowerCase().indexOf(termLower) > -1;
    });
    suggest(filtered);
  },
  renderItem: function(item, escapeValue){
    return<div><strong>${escapeValue(item)}</strong></div>;
  },
  onSelect: function(event, suggestion){
    alert('You selected: ' + suggestion.value);
  }
});

多语言支持

内置多种语言支持，可以通过设置locale选项来切换语言：

new Autocomplete({
  selector: '#my-input',
  minChars: 1,
  source: function(term, suggest){
    const termLower = term.toLowerCase();
    const filtered = data.filter(function(item){
      return item.toLowerCase().indexOf(termLower) > -1;
    });
    suggest(filtered);
  },
  onSelect: function(event, suggestion){
    alert('You selected: ' + suggestion.value);
  },
  locale: {
    hint: "Suggerimenti", // Placeholder for suggestions box
    selectAllText: "Seleziona tutto", // Text for select all button in multiple select box
    selectGroupText: "Tutti selezionati", // Text for select group button in multiple select box
    loadingText: "Caricamento...", // Text for loading state
    noResultsText: "Nessun risultato corrispondente {query}", // Text when no results match the input query
    noneResultsText: "Nessun risultati trovati {query}", // Text when no results found for the input query (when there are previous results)
    highlightNoneResultsText: "Nessun risultati trovati per <em>{query}</em>", // Text when no results found for the input query (when there are previous results and need to highlight)
    searchHint: "Cerca {query}", // Text for search input placeholder
    categoryAllText: "Tutto", // Text for "all categories" option in category selection box
    categoryFilterPlaceholder: "Filtra categorie...", // Placeholder text for category filter input box
    notACategoryText: "non è una categoria", // Text for non-category items in category selection box
    groupByText: "gruppi per {option}", // Text for group by options in multiple select box or combobox
    groupNoneOptionText: "non raggruppare", // Text for non grouping option in multiple select box or combobox
    groupSelectedText: "{optionCount} di {optionTotal} selezionati", // Text for grouped options in multiple select box or combobox (selected count)
    groupDisabledText: "{optionCount} di {optionTotal} disponibili", // Text for grouped options in multiple select box or combobox (disabled count)
    suggestMinCharsText: "Almeno {minChars} caratteri", // Text for minimum characters required in suggestions box or combobox (minChars value)
    loadingImageUrl: "/path/to/loading-image.gif", // URL of loading image for suggestions box or combobox (use with .showLoading method)
    showAllText: "Mostra tutti", // Text for show all button in suggestions box or combobox (use with .showAll method)
    hideAllText: "Nascondi tutti", // Text for hide all button in suggestions box or combobox (use with .hideAll method)
    showMoreText: "Più risultati", // Text for show more button in suggestions box or combobox (use with .showMore method)
    hideMoreText: "Meno risultati", // Text for hide more button in suggestions box or combobox (use with .hideMore method)
    onlyMatchText: "Solo risultati contenenti la ricerca", // Text for only matching results button in suggestions box or combobox (use with .onlyMatch method)
    onlyMatchPlaceholder: "Risultati contenenti la ricerca", // Placeholder text for only matching results input box in suggestions box or combobox (use with .onlyMatch method)
    clearSelectionButtonLabel: "Cancella scelta", // Text for clear selection button in suggestions box or combobox (use with .clearSelection method)
    clearSelectionPlaceholder: "Seleziona un'opzione per cancellare", // Placeholder text for clear selection input box in suggestions box or combobox (use with .clearSelection method)
    selectDeselectAllText: "Seleziona/Deseleziona tutto", // Text for select/deselect all button in suggestions box or combobox (use with .selectAll or .deselectAll methods)
    selectDeselectGroupText: "Seleziona/Deseleziona gruppo", // Text for select/deselect group button in suggestions box or combobox (use with .selectGroup or .deselectGroup methods)
    expandCollapseAllText: "Espandi/Comprimi tutto", // Text for expand/collapse all button in suggestions box or combobox (use with .expandAll or .collapseAll methods)
    expandCollapseGroupText: "Espandi/Comprimi gruppo", // Text for expand/collapse group button in suggestions box or combobox (use with .expandGroup or .collapseGroup methods)
    removeItemsText: "Rimuovi elementi", // Text for remove items button in suggestions box or combobox (use with .removeItems method)
    collapsePreviousText: "Collassabile precedente" // Text for collapse previous button in suggestions box or combobox (use with .collapsePrevious method)
  },
  onSelect: function(event, suggestion){
    alert('You selected: ' + suggestion.value);
  }
});

API文档

以下是autocomplete.js库的主要API文档：

new Autocomplete(options)

创建一个新的自动完成实例，参数如下：

selector：字符串，目标输入框的选择器。

minChars：整数，触发自动完成的最小字符数，默认为1。

source：函数，数据源函数，接收两个参数：查询字符串和回调函数，返回建议列表。

onSelect：函数，当选择某个建议时触发的回调函数，接收两个参数：事件对象和建议对象。

其他配置项：详见上述配置项说明。

instance.destroy()

销毁自动完成实例，释放资源。

const autocomplete = new Autocomplete('#my-input');
autocomplete.destroy();

instance.setOptions(options)

更新自动完成实例的配置项，参数为一个对象，包含需要更新的配置项。

const autocomplete = new Autocomplete('#my-input');
autocomplete.setOptions({ minChars: 2 });

instance.getOptions()

获取当前自动完成实例的所有配置项，返回一个对象。

const autocomplete = new Autocomplete('#my-input');
const options = autocomplete.getOptions();
console.log(options);

instance.enable()

启用自动完成功能。

const autocomplete = new Autocomplete('#my-input');
autocomplete.enable();

instance.disable()

禁用自动完成功能。

const autocomplete = new Autocomplete('#my-input');
autocomplete.disable();

instance.show()

显示建议列表，通常在输入框获得焦点时调用。

const autocomplete = new Autocomplete('#my-input');
autocomplete.show();

instance.hide()

隐藏建议列表，通常在输入框失去焦点时调用。

const autocomplete = new Autocomplete('#my-input');
autocomplete.hide();

instance.clearSuggestions()

清除当前的建议列表，通常在用户输入新的内容时调用。

const autocomplete = new Autocomplete('#my-input');
autocomplete.clearSuggestions();

instance.setSource(sourceFunction)

更新数据源函数，参数为一个新的数据源函数。

const autocomplete = new Autocomplete('#my-input');
autocomplete.setSource(function(term, suggest){
  const termLower = term.toLowerCase();
  const filtered = data.filter(function(item){
    return item.toLowerCase().indexOf(termLower) > -1;
  });
  suggest(filtered);
});

instance.setRenderItem(renderFunction)

更新每个选项的HTML结构函数，参数为一个新的渲染函数。

const autocomplete = new Autocomplete('#my-input');
autocomplete.setRenderItem(function(item, escapeValue){
  return<div><strong>${escapeValue(item)}</strong></div>;
});

instance.setLocale(localeObject)

更新语言配置项，参数为一个新的语言对象，示例如下：

const autocomplete = new Autocomplete('#my-input');
autocomplete.setLocale({ hint: "Suggerimenti" }); // 仅更新hint文本，其余保持默认值

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