Extremely light weight way to resolve jsonschema '$ref' references & inheritance: create circular/graphs, fractals from json (browser/coffeescript/javascript).

Stop processing json tree-structures, think json references and extentions.

Usage

nodejs:

jref = require('json-ref-parser')

Rule of thumb

When referencing to keys, always use underscores. Not doing this will not resolve references correctly.

Features

Feature	Notation
resolving (old) jsonschema references to 'id'-fields	"$ref": "foobar"
resolving (new) jsonschema internal jsonpointers	"$ref": "#/foo/value"
resolving positional jsonpointers	"$ref": "#/foo/bar[2]"
resolving grouped jsonpointers	"$ref": [{"$ref": "#/foo"},{"$ref": "#/bar}] for building jsongraphs
evaluating positional jsonpointer function	"$ref": "#/foo/bar()"
resolving local files	"$ref": "/some/path/test.json"
resolving remote json(schema) files	"$ref": "http://foo.com/person.json"
resolving remote jsonpointers	"$ref": "http://foo.com/person.json#/address/street"
evaluating jsonpointer notation in string	foo_{#/a/graph/value}
evaluating dot-notation in string	foo_{a.graph.value}

Developer tools:

Feature	Howto
console.log debug output	jref.debug = true
redefine ref token	jref.reftoken = '@ref'
redefine extend token	jref.extendtoken = '@extend'
redefine jsonpointer starttoken	jref.pathtoken = '#'
redefine resolve tokens	jref.resolvetoken = '@res'

NOTE: re-defining tokens is useful to prevent resolving only certain references. A possible rule of thumb could be to have '$ref' references for serverside, and '@ref' references for clientside when resolving the same jsondata.

Example: id fields

json = {
  foo: {
    id: 'foobar',
    value: 'bar'
  },
  example: {
    '$ref': 'foobar'
  }
};

outputs:

{
  foo: { id: 'foobar', value: 'bar' },
  example: {
    '$ref': 'foobar',
    '$res': { value: 'bar' }
}

Example: jsonpointers

{
  foo: {
    value: 'bar',
    foo: 'flop'
  },
  example: {
    ids: {
      '$ref': '#/foo/foo'
    }
  }
}

outputs:

{
  foo: {
    value: 'bar',
    foo: 'flop'
  },
  example: {
    ids: {
      '$ref': '#/foo/foo',
      '$res': 'flop'
    }
  }
}

NOTE: escaping slashes in keys is supported. "#/model/foo['\\/bar']/flop" will try to reference model.foo['/bar'].flop from itself

Example: remote schemas

{
  foo: {
    "$ref": "http://json-schema.org/address"
  }
  bar: {
    "$ref": "http://json-schema.org/address#/street/number"
  }
}

outputs: replaces value of foo with jsonresult from given url, also supports jsonpointers to remote source

NOTE: please install like so for remote support: 'npm install json-ref-lite sync-request'

Example: local files

{
  foo: {
    "$ref": "./test.json"
  }
}

outputs: replaces value of foo with contents of file test.json (use './' for current directory).

Example: array references

{
  "bar": ["one","two"],
  "foo": { "$ref": "#/bar[1]" }
}

outputs:

{
  "bar": ["one","two"],
  "foo": {
    "$ref": "#/bar[1]",
    '$res': "two"
  }
}

Example: evaluating functions

Ofcoarse functions fall outside the json scope, but they can be executed after binding them to the json.

json = {
  "bar": { "$ref": "#/foo()" }
}

json.foo = function(){ return "Hello World"; }

outputs:

{
  "bar": {
    "$ref": "#/foo()",
    '$res': "Hello World"
    }
}