执行 promise 或等待生成的字符串变量

Question

I am building a mongoose query and storing it in a variable call query . The code below shows it

let query = "Product.find(match)";
if (requestObject.query.sortBy) {
    query = query.concat(".", "sort(sort)");
    const parts = requestObject.query.sortBy.split(":");
    sort[parts[0]] = parts[1] === "desc" ? -1 : 1;
  }
  if (requestObject.query.fields) {
    query = query.concat(".", "select(fields)");
    const fields = requestObject.query.fields.split(",").join(" ");
    const items = await Product.find(match).sort(sort).select(fields); //.populate("category").exec();
    /**const items = await Product.find(match).sort(sort).select("-__v"); //.populate("category").exec();**/
  }

I am facing an issue when attempting to run a mongoose query that I have generated and stored in a string. When I run it in post man, the response is 200 but no data is returned. Below is a console.log(query) on line 2

what I hope to achieve is to have await or create a new promise execute the content id query variable like shown below

const items = new Promise((resolve) => resolve(query)); //.populate("category").exec();
  items
    ? responseObject.status(200).json(items)
    : responseObject
        .status(400)
        .json({ message: "Could not find products, please try again" });

I will appreciate it very much that and also if you can give me a better way of doing it, I will love that

Answer 1

This doesn't really make sense. You are building a string, not a query. You can't do anything with that string. (You could eval it, but you really shouldn't). Instead, build a query object!

let query = Product.find(match);
if (requestObject.query.sortBy) {
  const [field, dir] = requestObject.query.sortBy.split(":");
  const sort = {};
  sort[field] = dir === "desc" ? -1 : 1;
  query = query.sort(sort);
}
if (requestObject.query.fields) {
  const fields = requestObject.query.fields.split(",");
  query = query.select(fields);
}

//query.populate("category")

const items = await query.exec();
if (items) {
  responseObject.status(200).json(items)
} else {
  responseObject.status(400).json({ message: "Could not find products, please try again" });
}

If you really want to get that string for something (eg debugging), build it separately from the query:

let query = Product.find(match);
let queryStr = 'Product.find(match)';
if (requestObject.query.sortBy) {
  const [field, dir] = requestObject.query.sortBy.split(":");
  const sort = {[field]: dir === "desc" ? -1 : 1};
  query = query.sort(sort);
  queryStr += `.sort(${JSON.stringify(sort)})`;
}
if (requestObject.query.fields) {
  const fields = requestObject.query.fields.split(",");
  query = query.select(fields);
  queryStr += `.select(${JSON.stringify(fields)})`;
}

//query.populate("category")
//queryStr += `.populate("category")`;

console.log(queryStr);
const items = await query.exec();
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