SELECT json_set('[1,2,3]', '[1]', 5::json);
 json_set 
----------
 [1,5,3]
(1 row)

SELECT json_set('[1,2,3]', '[3]', 5::json);
 json_set 
----------
 [1,2,3]
(1 row)

SELECT json_set('[1,2,3]', '[2]', 5::json);
 json_set 
----------
 [1,2,5]
(1 row)

SELECT json_set('[1,2,3]', '[2]', '[0,1]'::json);
  json_set   
-------------
 [1,2,[0,1]]
(1 row)

SELECT json_set('  [ 1 ,   2,3]', '1', '5');
    json_set    
----------------
   [ 1 ,   5,3]
(1 row)

SELECT json_set('  [ 1 ,   [2,3],3]', '1', '5');
    json_set    
----------------
   [ 1 ,   5,3]
(1 row)

SELECT json_set('  [ 1 ,   [  2 ,   3     ],3]', '[1][0]', '5');
           json_set            
-------------------------------
   [ 1 ,   [  5 ,   3     ],3]
(1 row)

SELECT json_set('  [ 1 ,   [  2 ,   3     ],3]', '[5][0]', '5');
           json_set            
-------------------------------
   [ 1 ,   [  2 ,   3     ],3]
(1 row)

SELECT json_set('  [ 1 ,   [  2 ,   3     ],3]', '[4][0]', '5');
           json_set            
-------------------------------
   [ 1 ,   [  2 ,   3     ],3]
(1 row)

SELECT json_set('  [ 1 ,   [  2 ,   3     ],3]', '[3][0]', '5');
           json_set            
-------------------------------
   [ 1 ,   [  2 ,   3     ],3]
(1 row)

SELECT json_set('  [ 1 ,   [  2 ,   3     ],3]', '[2][0]', '5');
           json_set            
-------------------------------
   [ 1 ,   [  2 ,   3     ],3]
(1 row)

SELECT json_set('  [ 1 ,   [  2 ,   3     ],3]', '[1][0]', '   5  ');
           json_set            
-------------------------------
   [ 1 ,   [  5 ,   3     ],3]
(1 row)

SELECT json_set('  [ 1 ,   [  2 ,   3     ]  , 3  ] ', '[1][0]', '   5  ');
              json_set               
-------------------------------------
   [ 1 ,   [  5 ,   3     ]  , 3  ] 
(1 row)

SELECT json_set('  [ 1 ,   [  2 ,   3     ]  , 3  ] ', '[1 ][0]', '   5  ');
              json_set               
-------------------------------------
   [ 1 ,   [  5 ,   3     ]  , 3  ] 
(1 row)

SELECT json_set('  [ 1 ,   [  2 ,   3     ]  , 3  ] ', '[1 ][0]', '     5  ');
              json_set               
-------------------------------------
   [ 1 ,   [  5 ,   3     ]  , 3  ] 
(1 row)

SELECT json_set('  [ 1 ,   [  2 ,   3     ]  , 3  ] ', '[1 ][0]', $$     "hello\tworld"  $$);
                     json_set                     
--------------------------------------------------
   [ 1 ,   [  "hello\tworld" ,   3     ]  , 3  ] 
(1 row)

SELECT json_set('  [ 1 ,   [  2 ,   3     ]  , 3  ] ', '[1 ][0]', $$     "hello\u0009world"  $$);
                       json_set                       
------------------------------------------------------
   [ 1 ,   [  "hello\u0009world" ,   3     ]  , 3  ] 
(1 row)

SELECT json_set('  [ 1 ,   [  2 ,   3     ]  , 3  ] ', '[1 ][*]', $$     "hello\u0009world"  $$);
                               json_set                                
-----------------------------------------------------------------------
   [ 1 ,   [  "hello\u0009world" ,   "hello\u0009world"     ]  , 3  ] 
(1 row)

SELECT json_set('  [ 1 ,   [  2 ,   3     ]  , 3  ] ', '$', $$     "hello\u0009world"  $$);
       json_set        
-----------------------
   "hello\u0009world" 
(1 row)

SELECT json_set('       [ 1 ,   [  2 ,   3     ]  , 3  ] ', '$', $$     "hello\u0009world"  $$);
          json_set          
----------------------------
        "hello\u0009world" 
(1 row)

-- Since JavaScript doesn't do anything when you assign to a character subscript,
-- neither will json_set.
SELECT json_set('"hello"', '[0]', '"H"');
 json_set 
----------
 "hello"
(1 row)

SELECT json_set('"hello"', '[0][0]', '"H"');
 json_set 
----------
 "hello"
(1 row)

SELECT json_set('["hello"]', '[0][0]', '"H"');
 json_set  
-----------
 ["hello"]
(1 row)

SELECT json_set('["hello"]', '[0][0][0]', '"H"');
 json_set  
-----------
 ["hello"]
(1 row)

SELECT json_set('[0,1,2,[3,4,5],4]', '$[*]', '["set"]');
                 json_set                  
-------------------------------------------
 [["set"],["set"],["set"],["set"],["set"]]
(1 row)

SELECT json_set('[0,1,2,[3,4,5],4]', '$[*][*]', '["set"]');
              json_set               
-------------------------------------
 [0,1,2,[["set"],["set"],["set"]],4]
(1 row)

SELECT json_set('[0,1,2,[3,4,5],4]', '$..[*]', '["set"]');
                 json_set                  
-------------------------------------------
 [["set"],["set"],["set"],["set"],["set"]]
(1 row)