splitText文本打散分离

const splitText = (el, options = {}) => {
    const {
        splitRegex,
        tagName,
        classPrefix
    } = {
        splitRegex: null,
        tagName: 'span',
        classPrefix: 'char',
        ...options
    }

    // 删除空的、合并相邻的文本节点
    el.normalize()
    let count = 1

    const inject = el => {
        const parentNode = el.parentNode
        const str = el.nodeValue
        const split = splitRegex ? str.split(splitRegex) : str
        const l = split.length
        let i = -1
        while (++i < l) {
            const node = document.createElement(tagName)
            if (classPrefix) {
                node.className = classPrefix + count
                count++
            }
            node.appendChild(document.createTextNode(split[i]))
            node.setAttribute('aria-hidden', 'true')
            parentNode.insertBefore(node, el)
        }
        if (str.trim() !== '') {
            // 无障碍
            parentNode.setAttribute('aria-label', str)
        }
        parentNode.removeChild(el)
    }

    (function traverse(el) {
        // el为文本节点
        if (el.nodeType === 3) {
            return inject(el)
        }

        const childNodes = [].slice.call(el.childNodes)
        const l = childNodes.length

        // el只有一个子文本节点
        if (l === 1 && childNodes[0].nodeType === 3) {
            return inject(childNodes[0])
        }

        // el有多个子文本节点
        let i = -1
        while (++i < l) {
            traverse(childNodes[i])
        }
    }(el))
}