Case Insensitive Search with Regex

Richard_Kaplan · 2021-08-21T18:01:54.016Z

I am trying to do a case-insensitive search using Regex - the documentation gives examples with literal strings but I am trying this using a variable instead. This search works but only with matching case - how can I make it case insensitive?

exports=function (payload) {
  
  const query={"dt_name" : {'$regex':"^"+payload.query.testparam.toString()+"$"}};
  const mongodb=context.services.get("mongodb-atlas");
  const mycollection = mongodb.db("dt3_api").collection("LCP Production");
 
return mycollection.find(query).limit(10).toArray();
};

HomAskIe · 2021-08-23T10:01:49.048Z

Hello! @Richard_Kaplan .

By adding the i option in the regex pattern to perform a case-insensitive match for documents:

e.g

db.collection.find({name:{'$regex' : '^string$', '$options' : 'i'}})

More info: https://docs.atlas.mongodb.com/schema-suggestions/case-insensitive-regex/

Hope this helps

Richard_Kaplan · 2021-08-23T17:43:10.320Z

@HomAskIe

Thank you - that works if I literally hard code a string

What is the syntax if the string is in a variable - specifically a parameter from the URL i.e. payload.query.testparam

Richard_Kaplan · 2021-08-24T01:22:10.924Z

I tried this and various similar configurations:

return mycollection.find ({ "dt_name": { '$regex' : new RegExp(param1, $options:'i') } });

But I get:

“error”: “(BadValue) $regex has to be a string”

HomAskIe · 2021-08-24T01:49:02.036Z

Ah I see. $regex expects the pattern to be a string or an expression. If you’d like to use RegExp then you need to convert it to string.

RegExp toString(): RegExp.prototype.toString() - JavaScript | MDN

You code might become:

return mycollection.find ({"dt_name": { '$regex' : new RegExp(param1).toString(), $options: 'i' } });

You can include insensitive within RegExp too.

developer.mozilla.org

RegExp.prototype.ignoreCase - JavaScript | MDN

The ignoreCase accessor property indicates whether or not the i flag is used with the regular expression.

then it might become

return mycollection.find ({"dt_name": { '$regex' : new RegExp(param1, "i").toString()} });

notice there is an “i” right after param1.

Hope this helps. Thank you

Richard_Kaplan · 2021-08-24T02:25:06.938Z

HomAskIe:

return mycollection.find ({"dt_name": { '$regex' : new RegExp(param1, "i").toString()} });

Much appreciated

I get no error now, but the result of the find is always blank with either syntax. Even if I replace param1 with the desired parameter in quotes the find is always blank.

However this more simplified version does work - but only as a case-sensitive search:

return mycollection.find ({"dt_name":param1});

How do I get it to work not as a case-sensitive search?

HomAskIe · 2021-08-24T02:32:23.630Z

hum… interesting. Could you share with me some sample of your data?

Richard_Kaplan · 2021-08-24T02:55:28.660Z

See private message… thanks

HomAskIe · 2021-08-24T04:04:17.431Z

I’m not 100% sure why that’s not working for you because It works for me.

What is the value of param1 look like?

Try to make a loop to log each doc after before return see what is the output.
Something like:

data = mycollection.find ({"dt_name": { '$regex' : new RegExp("Kaplan", "i").toString()} });
// or
// data = mycollection.find ({"dt_name": { '$regex' : 'Kaplan', "$options": "i" } });
for (const d of data) {
    console.log(d);
}
return data

Richard_Kaplan · 2021-08-24T05:06:07.421Z

You can see param1 as testparam in Postman - It is currently set as Kaplan and I am hoping for it to work with both Kaplan and kaplan

Your proposed code as a Realm function yields this:

image754×158 19.2 KB

Realm looks like this:

image1135×670 77.3 KB

HomAskIe · 2021-08-24T08:09:22.095Z

I see. Could you let me know which mongo driver you are using?

Try this to see it work

const param1 = "kaplan"  // You might change this to be dynamic from query string
const docs = mycollection.find({
    "dt_name": {
        "$regex": param1, "$options": "i"
    }
});
const data = await docs.toArray();
console.log("Doc Len", data.length);
return data;

Richard_Kaplan · 2021-08-24T08:22:18.610Z

HomAskIe:

const param1 = "kaplan"  // You might change this to be dynamic from query string
const docs = mycollection.find({
    "dt_name": {
        "$regex": param1, "$options": "i"
    }
});
const data = await docs.toArray();
console.log("Doc Len", data.length);
return data;

MongoDB 4.4.8

That code in Realm gives me this error shown on top:

image1293×843 97.9 KB

HomAskIe · 2021-08-24T09:00:03.559Z

Ah that’s on Realm Function Editor! My bad. Even I’m new to that tool as well ha ha

All right, I just set up Realm and figure it out.
Try this simple way. It works for me on Ream as well.

const docs = mycollection.find({
    "dt_name": {
        "$regex": param1,
        "$options": "i"
    }
});
return data;

Have you tried this way?

Richard_Kaplan · 2021-08-24T11:31:24.322Z

I think you meant const data instead of const docs

Yes it works that way! Huge thanks!!!

Can you explain why the other methods did not work?

HomAskIe · 2021-08-25T03:03:59.576Z

Hi! I’ve been trying to make it works with RegExp on Realm but have not solved it yet.
It seems like the the slashes when convert a RegExp object to string is the problem.
e.g
This won’t work

let pattern = new RegExp("abc").toString()
console.log(pattern);
"/abc/"

system · 2021-08-30T03:04:31.795Z

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