JSON Templating Language

A tiny language that defines a simple, familiar interface to substitute JSON into strings.

What is this?

A Javascript implementation of the JSON Template Language as defined in the JSON Template Language Draft.

What is it used for?

Specifying interfaces, runtime expression mapping, other forms of programmatically interacting with JSON and URIs.

Why?

• specifying interfaces
  • easily identify and describe the object and array parts of a template.
  • define computed links.
• runtime usage
  • a simple and restricted embedded template language.
• interopability between JSON, URIs specifications
  • its just JSON -- nothing new to learn.
  • familiar Javascript template syntax.

Usage

To use the Javascript client you can:

Install it:

npm install @etclabscore/string-json-template-language --save

Import it:

import compileTemplate from "@etclabscore/string-json-template-language";

Use it somewhere:

const parsedJson = JSON.parse('{ "foo": "bar" }');
const template = "${foo}";
const resultString = compileTemplate(parsedJson, template);
// => "bar"

How does it work?

for the given JSON:

{
  "query": {
    "number": 1,
    "salad": "potato"
  }
}

and the given template:

http://www.example.com/foo?number=${query.number}&salad=${query.salad}
                                    \__________/          \__________/
                                         |                     |
                                         |                     |
      For each key in given JSON, substitute it by key into the string.

result:

 http://www.example.com/foo?number=1&salad=potato

Accessing Array indicies

for the given JSON

{
  "query": {
    "numbers": [0, 1, 2, 3],
    "salads": ["caesar", "potato"]
  }
}

and the given template:

http://www.example.com/foo?number=${query.numbers[1]}&salad=${query.salads[1]}
                                     \_____________/          \_____________/
                                           |                         |
                                           |                         |
      For each key in given JSON, subtitute it by array index into the string.

result:

 http://www.example.com/foo?number=1&salad=potato