jsonb_apply: Postgres JSON with a functional twist

Have you ever wanted to apply a function to a jsonb object, both dynamically and recursively?

No? Well, here's a Postgres extension that allows you to do just that:

Usage

select jsonb_apply(doc jsonb, func text[, variadic "any" args1_n]);

Examples

select jsonb_apply('{
  "id": 1,
  "name": "John",
  "messages": [
    "hello"
  ]
}', 'upper');

                   jsonb_apply                    
--------------------------------------------------
 {"id": 1, "name": "JOHN", "messages": ["HELLO"]}
(1 row)

select jsonb_apply('{
  "id": 1,
  "name": "John",
  "messages": [
    "hello"
  ]
}', 'replace', 'hello', 'bye');

                  jsonb_apply                   
------------------------------------------------
 {"id": 1, "name": "John", "messages": ["bye"]}
(1 row)

select jsonb_apply('{
  "id": 1,
  "name": "  John ",
  "messages": [
    "    hELLo  "
  ]
}', 'btrim');

                   jsonb_apply                    
--------------------------------------------------
 {"id": 1, "name": "John", "messages": ["hELLo"]}
(1 row)

select jsonb_apply('"abc~@~def~@~ghi"', 'split_part', '~@~', 2);

 jsonb_apply 
-------------
 "def"
(1 row)

Installation

cd /tmp
git clone https://github.com/Florents-Tselai/jsonb_apply.git
cd jsonb_apply
make
make install # may need sudo

create extension jsonb_apply;

Notes

select jsonb_apply(doc jsonb, func text[, variadic "any" args1_n]);

Currently only functions with signature like func(text, arg1 "any", ...) → text are supported. The first argument arg0 should be text and is taken as the jsonb string value (or array element) currently being processed. The variadic arguments (if any) will be passed to func as args1...argsn. Bot the function name and the types of variadic arguments will be used to search for the appropriate function in the catalog.