How to use $regex in mongoDB query with string variable?

Question

I am trying to do a simple wildcard query in a MongoDB database using a user-generated string variable. For example, if the user searches 'Bu', things like 'Burger' and 'Burger King' should be returned from the database. I have searched and tried several things but nothing seems to work. Any help would be greatly appreciated. Note: This is client-side JS.

    var text = document.getElementById("Search_Box").value;

    var regex = new RegExp(text + ".*");

    client.login().then(() => db.collection('businesses')
        .find({name:{$regex:regex}}).then(docs => {
          console.log("[MongoDB Stitch] Connected to Stitch");

As opposes to something like Node. I just wanted to be clear because sometimes they work differently. — RyanJLeonard
– RyanJLeonard, Commented Nov 17, 2017 at 20:32

Community · Accepted Answer · 2020-06-20 09:12:55Z

5

If you had the following documents:

{
    "_id" : ObjectId("5a0f3a464d8a2fe38bec4e92"),
    "name" : "Burger"
}

{
    "_id" : ObjectId("5a0f3a464d8a2fe38bec4e94"),
    "name" : "Burger King"
}

{
    "_id" : ObjectId("5a0f3a464d8a2fe38bec4e96"),
    "name" : "Booby's"
}

{
    "_id" : ObjectId("5a0f3a464d8a2fe38bec4e98"),
    "name" : "McDonald"
}

Starting with

To get everything starting with "Bu" you could do

db.collection('businesses').find({name: {$regex: '^Bu'}})

or

db.collection('businesses').find({name: {$regex: /^Bu/}})

In the middle of

If you needed anything that contained "Ki.*g" anywhere in the word you could do:

db.collection('businesses').find({name: {$regex: 'Ki.*g'}})

or

db.collection('businesses').find({name: {$regex: /Ki.*g/}})

Do the effort and go through the documentation. Everything is explained there, with a lot more details. https://docs.mongodb.com/manual/reference/operator/query/regex/

edited Jun 20, 2020 at 9:12

CommunityBot

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answered Nov 17, 2017 at 19:55

Alex P.

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2 Comments

RyanJLeonard Over a year ago

I understand how to do regex when you hardcode it as you did. My problem is using a string variable because regex does not accept strings.

Alex P. Over a year ago

then why don't you build the regex in a different variable and pass it in your RegExp() constructor? var stringRegex = text + ".*"; and then new RegExp(stringRegex);. Are we talking about the same RegExp? developer.mozilla.org/de/docs/Web/JavaScript/Reference/…

RakMaster · Accepted Answer · 2018-01-01 22:31:25Z

-1

I'm having a similar problem. I'm sending:

async search (term) {
  this.suggestions = await this.db.collection(this.collection).find({name: {$regex: term + '.*', $options: 'i'}}).sort({'_id': 1}).execute()
}

And I'm getting this back from Mongo

Stack Trace:
StitchError: $regex requires regular expression
at find (<native code>)
at apply (<native code>)
at executeServiceFunction (<anonymous>:10:10)
{
  "service": "mongodb-atlas",
  "name": "find",
  "arguments": [
    {
      "database": "monsters",
      "collection": "monsters",
      "query": {
        "name": {
          "$regex": "Aart.*",
          "$options": "i"
        }
      },
      "project": null,
      "sort": {
        "_id": {
          "$numberInt": "1"
        }
      }
    }
  ]
}

answered Jan 1, 2018 at 22:31

RakMaster

11 bronze badge

1 Comment

vandench Over a year ago

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