37 lines
1.3 KiB
JavaScript
37 lines
1.3 KiB
JavaScript
// utils/resultSectionScrollSync.js
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// 四测结果页共享：scroll 节流 + 计算当前 activeSection，回写 chip 高亮
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// 用法：
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// const scrollSync = require('../../utils/resultSectionScrollSync')
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// <scroll-view ... bindscroll="onScroll" />
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// onScroll(e) { scrollSync.onScroll(this, e) }
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const THROTTLE_MS = 140
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// chip 条 + 安全间距，单位 px（boundingClientRect 返回 px）
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const OFFSET_TOP = 70
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function onScroll(page, _e) {
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if (!page || !page.data || !Array.isArray(page.data.sectionNav) || !page.data.sectionNav.length) return
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const now = Date.now()
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if (page._scrollThrottleAt && now - page._scrollThrottleAt < THROTTLE_MS) return
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page._scrollThrottleAt = now
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const ids = page.data.sectionNav.map((item) => item.id).filter(Boolean)
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if (!ids.length) return
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const query = wx.createSelectorQuery().in(page)
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ids.forEach((id) => query.select('#' + id).boundingClientRect())
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query.exec((res) => {
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let current = ids[0]
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for (let i = 0; i < ids.length; i++) {
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const r = res[i]
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if (r && typeof r.top === 'number' && r.top - OFFSET_TOP <= 0) {
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current = ids[i]
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}
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}
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if (current && current !== page.data.activeSection) {
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page.setData({ activeSection: current })
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}
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})
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}
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module.exports = { onScroll }
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