如果 class 列表包含多个特定的 class

Question

如果元素 recordplayerstick 包含 pinplace 或 pinsongplay class，我需要一个函数来触发。我目前的代码 returns 有语法错误。正确的做法是什么？

if (document.getElementById('recordplayerstick').classList.contains('pinplace pinsongplay')) {
    removepin();
}

Answer 1

如果要使用 classList，则必须进行两次检查。

function removepin() {
  console.log("yep");
}
var cList = document.getElementById('recordplayerstick').classList;
if (
  cList.contains('pinplace') ||
  cList.contains('pinsongplay')) {
  removepin();
}

<div id="recordplayerstick" class="pinplace pinsongplay"></div>

Answer 2

由于 Element.classList.contains 只接受一个 class 名称，您需要分别检查每个名称。

您可以使用 Array.prototype.some() 来避免编写一堆或条件

const el = document.getElementById('recordplayerstick')
const classNames = ['pinplace', 'pinsongplay']
if (classNames.some(className => el.classList.contains(className))) {
  removeping()
}

Answer 3

前面的回答已经说明了.classList.contains()只能传递一个参数。以下示例具有一个函数，该函数将遍历给定的 classNames° 和 returns true 列表，如果 classNames 中的任何或所有¹被分配给目标 DOM节点².

°第三个参数...类
¹ 第二个参数 all
² 第一个参数 DOMNode

用法

findClasses(DOMNode, all, ...classes)
DOMNode.....: The reference to a single DOM element
              ex. const node = document.querySelector('.target'); 
all.........: Boolean to determine whether all classes listed in the 
              third parameter need to be present (true) or just one of
              them (false)
...classes..: ClassNames as a comma delimited list of strings
              ex. "bullseye", "miss"

例子

const node = document.querySelector('#recordplayerstick');

const findClasses = (node, all, ...classes) => {
  return all ?
    classes.every(cls => node.classList.contains(cls)) :
    classes.some(cls => node.classList.contains(cls));
};

// console.log(findClasses(node, false, 'pinplace', 'pinsongplay'));
// returns true

// console.log(findClasses(node, true, 'pinplace', 'pinsongplay'));
// returns false

const removePin = () => alert(`PIN REMOVED!`);

if (findClasses(node, false, 'pinplace', 'pinsongplay')) removePin();

<div id='recordplayerstick' class='pinplace'></div>

Answer 4

使用... (Spread syntax)

例子

const element = document.getElementById("left-sidebar");
const has_some = ["left-sidebar", "js-pinned-left-sidebar"];
const result = [...element.classList].some(className => has_some.indexOf(className) !== -1);  
// has_some.some(className => [...element.classList].indexOf(className) !== -1);
// or example like @Phil
// has_some.some(className => element.classList.contains(className))

功能齐全

/**
 * @description determine if an array contains one or more items from another array.
 * @param {array} haystack the array to search.
 * @param {array} arr the array providing items to check for in the haystack.
 * @return {boolean} true|false if haystack contains at least one item from arr.
 */
var findOne = function (haystack, arr) {
    return arr.some(function (v) {
        return haystack.indexOf(v) !== -1;
    });
};

/**
 * @description determine if element has one or more className.
 * @param {HTMLElement} element element where is going to search classNames.
 * @param {array} arrayClassNames Array of Strings, provide to search ClassName in the element
 * @return {boolean} true|false if element.classList contains at least one item from arrayClassNames.
 */
var checkElementHasSomeClassName = function (element, arrayClassNames) {
    // uncoment and use this return if you don't want the findOne function
    // return [...element.classList].some(className => arrayClassNames.indexOf(className) !== -1);
    return findOne([...element.classList], arrayClassNames);
};

附加链接：

Spread syntax - browser compatibility

Check if exist one item from array in another array

Answer 5

您可以使用正则表达式：

let div = document.querySelector("div");

if ( /bubu|moo|bar/i.test(div.className) ) {
  console.log("ok (simple test)");
}

if ( /default|bar/i.test(div.className) ) {
  console.log("not-ok (partial match of `btn-default`)");
}

if ( /(?:^|\s)default|bar(?:\s|$)/i.test(div.className) ) {
  console.log("ok (not logging)");
  // ^ - the beginning of line | or \s space character.
  // space char | or $ - line ending
}

/***/

let names = ["btn", "bar", "bubu"];
let regex = new RegExp( "(?:^|\s)" + names.join("|") + "(?:\s|$)", "i");

if ( regex.test(div.className) ) {
  console.log("ok (new RegExp)");
}

<div class="btn btn-default bubu"></div>

如果 class 列表包含多个特定的 class

If classlist contains more than one specific class

javascript

class

contains

用法

例子