如何迭代數組並根據 PostgreSQL 查詢的結果構造對象

Question

這是我的問題：

var ps = ["P1", "P2"];
var hs = ["H1", "H2"];

var jOut = {};

hs.forEach(async (h) => {
    var t = `t_${h}`;
    var query = {
        text: `SELECT pName, pPrice FROM ${t} WHERE pName = ANY($1)`,
        values: [ps],
        rowMode: "array"
    };

    var qres = await client.query(query);
    jOut[t] = qres.rows;
});

console.log(jOut);

我希望輸出看起來像這樣：

{
    t_H1: [ [pName: "P1", pPrice: 0.5], [pName: "P2", pPrice: 1.2] ],
    t_H2: [ [pName: "P1", pPrice: 0.6], [pName: "P2", pPrice: 1.0] ]
}

但相反，我的輸出如下所示：

{}

Answer 1

forEach循環不會等待 promise 被解決，這就是為什么

console.log(jOut);

在解決所有/任何承諾之前立即執行。

而是使用for..of循環

for(const h of hs) {
 var t = `t_${h}`;
    var query = {
        text: `SELECT pName, pPrice FROM ${t} WHERE pName = ANY($1)`,
        values: [ps],
        rowMode: "array"
    };

    var qres = await client.query(query);
    jOut[t] = qres.rows;
}
console.log(jOut);