Bringing psql’s \d to your web browser

  % psql db_name
  
  (1)=# \set ECHO_HIDDEN
  
  (1)=# \d
  ********* QUERY **********
  SELECT n.nspname as "Schema",
    c.relname as "Name",
    CASE c.relkind WHEN 'r' THEN 'table' WHEN 'v' THEN 'view' WHEN 'm' THEN 'materialized view' WHEN 'i' THEN 'index' WHEN 'S' TH
  EN 'sequence' WHEN 't' THEN 'TOAST table' WHEN 'f' THEN 'foreign table' WHEN 'p' THEN 'partitioned table' WHEN 'I' THEN 'partit
  ioned index' END as "Type",
    pg_catalog.pg_get_userbyid(c.relowner) as "Owner"
  FROM pg_catalog.pg_class c
       LEFT JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace
       LEFT JOIN pg_catalog.pg_am am ON am.oid = c.relam
  WHERE c.relkind IN ('r','p','v','m','S','f','')
        AND n.nspname <> 'pg_catalog'
        AND n.nspname !~ '^pg_toast'
        AND n.nspname <> 'information_schema'
    AND pg_catalog.pg_table_is_visible(c.oid)
  ORDER BY 1,2;
  **************************
  
                            List of relations
   Schema │                  Name                  │   Type   │ Owner
  ────────┼────────────────────────────────────────┼──────────┼────────
  ...

I'm not sure if I entirely follow what translating C to JS gives you, other than a bit of (fairly simple) parsing of \cmd and flags? I didn't look too carefully at the code, so maybe I'm missing something.

    From the Postgres master branch (17devel), we take exec_command_d, exec_command_list and exec_command_sf_sv from command.c, and all of describe.c and sql_help.c, from src/bin/psql.
    We use plenty of RegExp search-and-replace to turn this C code into valid JS syntax.
    We implement some C library functions, such as strlen and strchr, and some Postgres support functions, such as printTable and printQuery, in JavaScript.