plv8: JavaScript Language
The plv8 extension allows you use JavaScript within Postgres.
Overview
While Postgres natively runs SQL, it can also run other "procedural languages".
plv8 allows you to run JavaScript code - specifically any code that runs on the V8 JavaScript engine.
It can be used for database functions, triggers, queries and more.
Enable the extension
- Go to the Database page in the Dashboard.
- Click on Extensions in the sidebar.
- Search for "plv8" and enable the extension.
Create plv8 functions
Functions written in plv8 are written just like any other PostgreSQL functions, only
with the language identifier set to plv8.
_10create or replace function function_name()_10returns void as $$_10 // V8 JavaScript_10 // code_10 // here_10$$ language plv8;
You can call plv8 functions like any other Postgres function:
_10select function_name();
Examples
Scalar functions
A scalar function is anything that takes in some user input and returns a single result.
_10create or replace function hello_world(name text)_10returns text as $$_10_10 let output = `Hello, ${name}!`;_10 return output;_10_10$$ language plv8;
Executing SQL
You can execute SQL within plv8 code using the plv8.execute function.
_10create or replace function update_user(id bigint, first_name text)_10returns smallint as $$_10_10 var num_affected = plv8.execute(_10 'update profiles set first_name = $1 where id = $2',_10 [first_name, id]_10 );_10_10 return num_affected;_10$$ language plv8;
Set-returning functions
A set-returning function is anything that returns a full set of results - for example, rows in a table.
_11create or replace function get_messages()_11returns setof messages as $$_11_11 var json_result = plv8.execute(_11 'select * from messages'_11 );_11_11 return json_result;_11$$ language plv8;_11_11select * from get_messages();
Resources
- Official
plv8documentation - plv8 GitHub Repository