Question 116126 in Mongodb Question posted in
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mongodb find: how to use a variable regexp inside $where?

I have a nodejs express web with a mongo db with

const AuthorSchema = new Schema({
    first_name: { type: String, required: true, maxLength: 100 },
    family_name: { type: String, required: true, maxLength: 100 },
    date_of_birth: { type: Date },
    date_of_death: { type: Date },
});

I want to search for an author using a regexp over the first_name + family_name. In other words,
given we have an author with:
…
first_name: ‘Alessandro’
family_name: ‘Manzoni’
…
I want to match it using all of the search strings:

‘Alessandro’ or ‘ale’ or ‘manzo’ or ‘alessandro manzoni’ or ‘Manzoni Alessandro’

so I wrote this:

const searchRegex = new RegExp(req.body.search_text, 'i');  
Author.find({ $where: 
    function() {
        return (searchRegex.test(this.first_name + " " + this.family_name) 
            || searchRegex.test(this.family_name + " " + this.first_name) )
    } 
},"_id").exec(function (err, list_authors) {

and I got:

MongoServerError: Executor error during find command :: caused by :: ReferenceError: searchRegex is not defined :
@:2:33

I tried using a $let clause but all I’ve achieved is getting all of the authors id in the results list.

Tags:

2

Answers


  1. Chosen as BEST ANSWER
    0

    Thanks, your answer works perfectly. I added a $or to search also in family_name + " " + first_name and deleted the options line because they are in the regex. So the final code is:

    Author.find({
  $or: [
    {
      "$expr": {
        "$eq": [
          {
            "$regexMatch": {
              "input": {
                "$concat": [
                  "$first_name",
                  " ",
                  "$family_name"
                ]
              },
              "regex": searchRegex
            }
          },
        true
      ]
    }
  }, {
    "$expr": {
      "$eq": [
        {
          "$regexMatch": {
            "input": {
              "$concat": [
                "$family_name",
                " ",
                "$first_name"
              ]
            },
            "regex": searchRegex
          }
        },
        true
      ]
    }
  },                    
]},"_id").exec(callback);

    Really a lot of code, but it works...


  2. 0

    I think you are looking for something like this (and avoiding $where which is very inefficient):

    This query get the first and family names concatenated and do the regex match on it.

    If there is a match in the regex (the result is true) the document will be returned. Otherwise it doesn’t.

    Author.find({
  "$expr": {
    "$eq": [
      {
        "$regexMatch": {
          "input": {
            "$concat": [
              "$first_name",
              " ",
              "$family_name"
            ]
          },
          "regex": yourStringRegexHere,
          "options": "i"
        }
      },
      true
    ]
  }
})

    Example here

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