How to use pattern matching with numbers using node.js and MongoDB

Question

I have several documents in a collection in MongoDB as shown in this snapshot . I'm creating a web app for which this is the back-end data.

Every document has an attribute name . The user has an option to search for the name in the front-end. Now, suppose the user searches for "Sam", then I'm returning the documents where name is either exactly "Sam" or starts with "Sam". I have implemented this using the following code:

let name = "^"+req.body.name;
const name_regex = new RegExp(name, 'gi');

try {
  let members = await Member.find({ name: req.body.name=="" ? /^$|/ : name_regex});
  res.send(members);
}

ie, if the user dosen't provide a name, return all documents, else return documents matching the regex.

So , if the user searches for "Sam", the output is all 3 documents since all of them have name starting with "Sam", but if the user searches for "Samm", then only one document is returned where the name is "Sammy".

Now, I want to implement the same logic on age attribute, ie, if the user searches for age: 2, then I want to return all documents where age is either exactly 2 or starts with the digit 2. But I'm unable to use the above method sine it only works with strings.

Note: I'm using mongoose package and Express framework.

Answer 1

You can do this:

// regular expression matching anything that starts with two 
const age_regex = /^2/; 

Member.find({
  $expr: {
    $regexMatch: {
      input: {
        $toString: "$age" // Casting the age value to a string
      },
      regex: age_regex
    }
  }
})

Some usefule explanatory links: $expr , $regexMatch , $toString