Replacing ObjectId with a String in JSON Using Regex
Problem
When working with MongoDB data dumps in JSON format, ObjectIDs are represented as:
"_id" : ObjectId("5e3b1890e032d225a091d43f"),
"userId" : ObjectId("65ed1c2c-922c-4c82-b5bc-7324f69eea10"),
However, for many use cases you need these values to be plain strings:
"_id" : "5e3b1890e032d225a091d43f",
"userId" : "65ed1c2c-922c-4c82-b5bc-7324f69eea10",
Approach
We can achieve this using Visual Studio Code’s Find and Replace with Regular Expressions.
Step 1: Open Find and Replace
- Press Ctrl+F (or Cmd+F on macOS) to open the search.
- Click the .* icon to enable regex search.
Step 2: Configure the Regex
Find Pattern:
ObjectId\("([0-9a-fA-F]{24})"\)
This pattern captures the 24 hexadecimal characters within ObjectId(“…”).
Replace With:
"$1"
The replacement uses the captured group ($1) to output just the string inside the ObjectId.
Example Transformation
"_id" : ObjectId("5e3b1890e032d225a091d43f"),
"userId" : ObjectId("65ed1c2c-922c-4c82-b5bc-7324f69eea10"),
Bonus: Replacing ISODate
If you also need to replace ISODate("...") with a plain string, use this pattern:
Find Pattern:
ISODate\("([^"]+)"\)
Replace With:
"$1"
This captures the date string inside ISODate and replaces the whole expression with just that string.