本組件是對 Element UI 中 el-tooltip 組件的二次封裝

新增特性：鼠標移入父節點時，根據內容是否溢出判斷是否顯示 Tooltip

el-tooltip 文檔

<template>
    <!-- 
        屬性
            content：el-tooltip 屬性，文本內容
            effect：el-tooltip 屬性，Tooltip 主題，默認 light
            placement：el-tooltip 屬性，Tooltip 顯示的方向，默認值為 top
     -->
    <el-tooltip :disabled="disabled" :content="content" :effect="effect" :placement="placement">
        <span class="j-tooltip" ref="content">{{content}}</span>
    </el-tooltip>
</template>

<script>

export default {
    name: 'JTooltip',
    props: {
        content: String,
        effect: {
            type: String,
            default: 'light'
        },
        placement: {
            type: String,
            default: 'top'
        }
    },
    data() {
        return {
            disabled: false
        }
    },
    mounted() {
        const parentNode = this.$refs.content.parentNode;
        parentNode.addEventListener('mouseenter', this.handleMouseenter);
    },
    methods: {
        handleMouseenter(e) {
            this.disabled = !this.textOverflow(e.target);
        },

        // 判斷文本是否溢出
        textOverflow(element) {
            const range = document.createRange();
            range.setStart(element, 0);
            range.setEnd(element, element.childNodes.length);
            const rangeWidth = range.getBoundingClientRect().width;
            const computed = window.getComputedStyle(element)
            const padding = (parseInt(computed.paddingLeft, 10) || 0) + (parseInt(computed.paddingRight, 10) || 0);

            return rangeWidth + padding > element.offsetWidth || element.scrollWidth > element.offsetWidth;
        },
    },
    beforeDestroy() {
        const parentNode = this.$refs.content.parentNode;
        if (parentNode) {
            parentNode.removeEventListener('mouseenter', this.handleMouseenter);
        }
    },
}
</script>

<style lang="scss" scoped>
.j-tooltip {
    white-space: nowrap;
    text-overflow: ellipsis;
    overflow: hidden;
}
</style>