使用模块化SDK v9的FIRESTORE条件WHERE子句

问题描述

如何使用Firebase模块化SDK(V9)执行带条件where()子句的查询？

名称分隔版本(V8)查询示例：

const status = "live"
const publishedAfter = 1630607348811

let q = firebase.firestore().collection("articles")

// filters selected by users
if (status) q = q.where("status", "==", "live")
if (publishedAfter) q = q.where("publishedAt", ">", publishedAfter)

const qSnapshot = await q.get()

推荐答案

选项1：有条件添加QueryConstraint以以前为基准

let q = query(collection(firestore, "articles"))

// filters selected by users
if (status) q = query(q, where("status", "==", "live"))
if (publishedAfter) q = query(q, where("publishedAt", ">", publishedAfter))

const qSnapshot = await getDocs(q);

选项2：有条件地将QueryConstraints添加到数组

const constraints = []

// filters selected by users
if (status) constraints.push(where("status", "==", "live"))
if (publishedAfter) constraints.push(where("publishedAt", ">", publishedAfter))

const q = query(collection(firestore, "articles"), ...constraints)

const qSnapshot = await getDocs(q);

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