在与mongoose查询配对的映射函数中，变量值不变

Question

我正在处理一个mern项目，在该项目中，我需要创建一个议程，该议程包含一个作为约会类型数组的属性。

在nodejs api中，我声明了一个var typeRefs=[]；如果类型模型中存在一个类型，我将其ref插入上一个数组，否则我创建该类型并将新类型ref插入前一个数组中，最后我基于typeRefs数组创建议程文档，但该数组在map函数范围外为空，在map函数范围内，我可以看到数组值发生了变化。

//议程模型

const agendaSchema = mongoose.Schema(
{
name: String,
types: [{ type: mongoose.Schema.Types.ObjectId, ref: "Type" }],
establishment: {
type: mongoose.Schema.Types.ObjectId,
ref: "Establishment",
},
template: { type: mongoose.Schema.Types.ObjectId, ref: "Template" },
isActive: { type: Boolean, default: true },
},
{ timestamps: true }
);
var Agenda = mongoose.model("Agenda", agendaSchema);
export default Agenda;

//型号

import mongoose from "mongoose";
const typeSchema = mongoose.Schema(
{
name: String,
duration: Number,
color: String,
online: { type: Boolean, default: true },
establishment: {
type: mongoose.Schema.Types.ObjectId,
ref: "Establishment",
},
},
{ timestamps: true }
);
var Type = mongoose.model("Type", typeSchema);
export default Type;

//用于议程创建的api函数

export const add = async (req, res) => {
var data = req.body;
try {
var typesRefs = [];
data.types.map((type) => {
Type.find({ name: type.text.toUpperCase() }, (err, res) => {
if (res.length === 0) {
const newType = new Type({
name: type.text.toUpperCase(),
establishment: data.establishment,
});
newType.save();
typesRefs = [...typesRefs, newType._id];
} else {
typesRefs = [...typesRefs, type._id];
}
});
});
console.log(typesRefs);
await Agenda.create({ ...data, types: typesRefs });
res.status(200).json({ message: "Agenda created successfully" });
} catch (error) {
console.log(error);
res.status(401).json({ message: "An error occured !" });
}
};

Answer 1

诀窍是使用for循环而不是map函数。

export const add = async (req, res) => {
var data = req.body;
var typeRefs = [];
try {
for (let i = 0; i < data.types.length; i++) {
const typeExist = await Type.find({
name: data.types[i].text.toUpperCase(),
});
if (typeExist.length === 0) {
const newType = await Type.create({
name: data.types[i].text.toUpperCase(),
establishment: data.establishment,
});
typeRefs = [...typeRefs, newType._id];
} else {
typeRefs = [...typeRefs, data.types[i]._id];
}
}
console.log(typeRefs);
await Agenda.create({ ...data, types: typeRefs });
res.status(200).json({ message: "Agenda created successfully" });
} catch (error) {
console.log(error);
res.status(401).json({ message: "An error occured !" });
}
};