Use mustache templates with PostgreSQL and JSONb inputs

Question

Is time to use JSONb datatype as input in a template, and PostgreSQL queries as template system... Mustache will be perfect, if there are some Mustache implementation for PLpgSQL (or adapted for C)... Seems there are no one.

But there are a good source-code for Javascript-mustache: how to use/adapt it for PLv8?

What the best way (performance) to call mustache many times in a context like
SELECT tplEngine_plv8(input_jsonb,tpl_mustashe) as text_result FROM t ?

---

NOTES for test and discuss

Test with: http://jsfiddle.net/47x341wu/

CREATE TABLE story (
  id int NOT NULL PRIMARY KEY,
  title text NOT NULL,
  UNIQUE(title)
);
CREATE TABLE story_character (
  id_story int REFERENCES story(id) NOT NULL,
  name text NOT NULL,
  UNIQUE(id_story,name)
);
INSERT INTO story (id,title) VALUES (1,'African jungle story'), 
  (2,'Story of India jungle');
INSERT INTO story_character(id_story,name) VALUES 
  (1,'Tarzan'), (1,'Jane'), (2,'Mowgli'), (2,'Baloo');

CREATE VIEW t AS 
  select id_story, jsonb_build_object('title',title, 
      'names', jsonb_agg( jsonb_build_object('name', name) )
   ) AS j
  from story s INNER JOIN story_character c ON s.id=c.id_story 
  group by id_story,title;

So with VIEW t we have names and titles for a mustache template,

SELECT tplEngine_plv8(
  j,
  '<br/>* <b>{{title}}</b> with: {{#names}} <i>{{name}}</i>; {{/names}}'
 ) as result
FROM t;

and compare it with the JSFiddle result.

---

Performance tests

Using EXPLAIN ANALYZE ... Perhaps adding a few hundreds of random values at the testing tables. And, testing also calling strategies: one at a time or by array.

CREATE FUNCTION mustache_engine(
  p_input JSONB, 
  p_template TEXT
) RETURNS TEXT language plv8 as $$
   // copy https://rawgit.com/janl/mustache.js/master/mustache.js
   // and somethings more
$$;

or

CREATE FUNCTION mustache_engine(
  p_inputs JSONB[],  -- many inputs 
  p_templates TEXT   -- one template
) RETURNS TEXT[]     -- many resuts
language plv8 as $$ ... $$;

CREATE FUNCTION mustache_engine(  -- many input-template pairs
  p_inputs JSONB[],   
  p_templates TEXT[]
) RETURNS TEXT[]     -- many resuts
language plv8 as $$ ... $$;

Answer 1

create or replace function mustache(template text, view json, partials   json) returns text
language plv8 as 
 << copy https://rawgit.com/janl/mustache.js/master/mustache.js >>
 var mustache=this.Mustache;
return mustache.render(template, view, partials)
 $$

;