页面tooltip组件限制工具函数使用示例详解

<el-form>
   <el-form-item label="姓名" prop="name">
       <el-tooltip :content="form.name">
           <el-input v-model="form.name" disabled="true"></el-input>
       </el-tooltip>
   </el-form-item>
   .....后续出现多个这样的元素
</el-form>

.el-input {
    text-overflow:ellipsis;
    white-space:nowrap;
    overflow:hidden;
}

function isTextOverflow(element) {
    // use range width instead of scrollWidth to determine whether the text is overflowing
    // to address a potential FireFox bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1074543#c3
    if (!element || !element.childNodes || !element.childNodes.length) {
        return false;
    }
    const range = document.createRange();
    range.setStart(element, 0);
    range.setEnd(element, element.childNodes.length);
    const rangeWidth = range.getBoundingClientRect().width;
    // if the element has padding style,should add the padding value.
    const padding = (parseInt(getStyle(element, 'paddingLeft'), 10) || 0) + (parseInt(getStyle(element, 'paddingRight'), 10) || 0);
    return rangeWidth + padding > element.offsetWidth || element.scrollWidth > element.offsetWidth;
}
function hasClass(el, cls) {
    if (!el || !cls) {
        return false;
    }
    if (cls.indexOf(" ") > -1) {
        return console.error(`className should not contain space!`);
    }
    if (el.classList) {
        return el.classList.contains(cls);
    } else {
        return (" " + el.className + " ").indexOf(" " + cls + " ") > -1;
    }
}
function camelCase(name) {
    return name.replace(/([\:\_\-]+(.))/g, (_, separator, letter, offset) => offset ? letter.toUpperCase() : letter).replace(/^moz([A-Z])/, "Moz$1")
}
// IE version more than 9
function getStyle(el, styleName) {
    if (!element || !styleName) return null;
    styleName = camelCase(styleName);
    if (styleName === 'float') {
        styleName = 'cssFloat';
    }
    try {
        var computed = document.defaultView.getComputedStyle(element, '');
        return element.style[styleName] || computed ? computed[styleName] : null;
    } catch (e) {
        return element.style[styleName];
    }
}

export function findToolTip(children,tooltips = []){
    //这里写代码
}

//参数1：子组件实例数组
//参数2：收集组件实例的数组
export function findToolTip(children,tooltips = []){
    for(let i = 0,len = children.length;i < len;i++){
        //递归条件
        if(Array.isArray(children[i]) && children[i].length){
            findToolTip(children[i],tooltips);
        }else{
            //判断如果doDestroy属性是一个方法，则代表是一个tooltip组件，添加到数组中
            if(typeof children[i].doDestroy === "function"){
                tooltips.push(children[i]);
            }
        }
    }
    //把收集到的组件实例返回
    return tooltips;
}
//调用方式，传入当前组件实例this对象的所有子组件实例
//如:findToolTip(this.$children)

// 参数1:当前组件实例this对象
// 参数2:用于获取被tooltip包裹的子元素的类名
export function isShowToolTip(vm,className="el-input"){
    //这里写代码
}

const res = Vue.compile(`<el-tooltip disabled><el-input value="${ child && child.innerText }" disabled></el-input></el-tooltip>`);
const reRender = new Vue({
    render:res.render,
    staticRenderFns:res.staticRenderFns
}).$mount(parent);//parent为获取的tooltip组件实例根元素

// 参数1:当前组件实例this对象
// 参数2:用于获取被tooltip包裹的子元素的类名
export function isShowToolTip(vm,className="el-input"){
    //为了确保能够获取到DOM元素，需要调用一次nextTick方法
    vm.$nextTick(() => {
        const allTooltips = findToolTip(vm.$children);
        allTooltips.forEach(item => {
            //获取子元素
            const child = item.$el.querySelector("." + className);
            //判断是否被截断
            if(!isTextOverflow(child)){
                //获取渲染元素
                const parent = item.$el;
                const res = Vue.compile(`<el-tooltip disabled><el-input value="${ child && child.innerText }" disabled></el-input></el-tooltip>`);
                const reRender = new Vue({
                    render:res.render,
                    staticRenderFns:res.staticRenderFns
                }).$mount(parent);
            }
        })
    }};
}

watch:{
    form(val){
        if(typeof val === "object" && val && Object.keys(val).length){
            //将this当做参数传入即可
            isShowToolTip(this);
        }
    }
}