zer

July 10, 2019 ยท View on GitHub

Zer helps you serialize any JavaScript chains to String representations of any languages by leveraging ES2015 Proxy objects.

Installation

npm install zer

Usage

Zer is currently useful for generating Gremlin-Groovy graph database queries.


import { gremlin, renderChain } from 'zer';

const { g, out, has } = gremlin;

const chain = g.V().has('name', 'Alice').repeat(out('knows')).until(has('name', 'Bob'));
const rendered_chain = renderChain(chain);

console.log(rendered_chain);
/*
 {
    query: 'g.V().has(p0, p1).repeat(out(p2)).until(has(p3, p4))',
    params: {
        p0: 'name',
        p1: 'Alice',
        p2: 'knows',
        p3: 'name',
        p4: 'Bob'
    }
 }
*/

console.log(chain.__repr__());
/*
 [
     ChainStart { name: 'g', type: 'CHAIN_START' },
     Step { name: 'V', type: 'STEP' },
     Arguments { params: [], type: 'ARGUMENTS' },
     Step { name: 'has', type: 'STEP' },
     Arguments { params: [ 'name', 'Alice' ], type: 'ARGUMENTS' },
     Step { name: 'repeat', type: 'STEP' },
     Arguments {
       params: [
         {
           query: 'out(p0)',
           params: {
             p0: 'knows'
           }
         }
       ],
       type: 'ARGUMENTS'
     },
     Step {
       name: 'until',
       type: 'STEP'
     },
     Arguments {
       params: [
         {
           query: 'has(p0, p1)',
           params: {
             p0: 'name',
             p1: 'Bob'
           }
         }
       ],
       type: 'ARGUMENTS'
     }
  ]
*/

Argument escaping

Zer allows you to output Objects, not just Strings. This is especially useful when you wish to escape some arguments from your chain, such as when creating a DSL for a database client (SQL, Gremlin...).

const chain = g.V().has('name', 'Alice').repeat(out('knows')).until(has('name', 'Bob'));

console.log(chain.__repr__())

/*
 { query: 'g.V().has(p0, p1).has(p2, p3).repeat(out(p4, p5))',
  params:
   {
     p0: 'name',
     p1: 'Alice',
     p2: 'age',
     p3: 30,
     p4: 'firstname',
     p5: 'Bob'
   }
*/