MongoDB Node.js to Replace String in Document

Today this article will see how to write a query using MongoDB Node.js to replace string or substring In a Document

We will replace a string in the Mongo document with the input string using a simple and easy approach i.e using $replaceOne aggregation operator which is supported in MongoDB v4.0 onwards.

We will cover below aspects,

We already looked at a simple way of adding or updating a new field to the document in our previous MongoDB sample series.

Getting started -MongoDB Node.js to Replace String

Here below is a sample schema or document we shall use,

Node.js – Replace Substring in MongoDB using replaceOne Aggregator

We are going to use a newly introduced aggregate operator to replace easily a string with matching criteria with part of the string.

Query Pattern Replace using $replaceOne

{ 
$replaceOne: { 
    input: <expression>, 
    find: <expression>, 
    replacement: <expression>}
}

In the above query,

You can replace the existing Mongo field using any other fields from the document using the above approach + using the approach discussed here.

Node.js Example using $replaceOne

In the below example, we will replace “total-order” with “order” in the mongo field.

Please add below using namespace

import { MongoClient } from 'mongodb';

Define the Regex query for the matching string,

'Link': {     
     '$regex': new RegExp('total-order')   
 }

Define the Set using replaceOne Operator,

'$set': {
      'Link': {
        '$replaceOne': {
          'input': '$Link', 
          'find': 'total-order', 
          'replacement': 'order'
        }
      }
    }

Example

const filter = {
  'Link': {
    '$regex': new RegExp('total-order')
  }
},[
  {
    '$set': {
      'Link': {
        '$replaceOne': {
          'input': '$Link', 
          'find': 'total-order', 
          'replacement': 'order'
        }
      }
    }
  }
];
const client = await MongoClient.connect(
  'mongodb://host/',
  { useNewUrlParser: true, useUnifiedTopology: true }
);

const coll = client.db('TheCodeBuzz').collection('Orders');
const cursor = coll.find(filter);
const result = await cursor.toArray();
await client.close();

Below is the schema post-update,

That’s all! Happy coding!

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