/deref

JSON-Schema $ref resolution

Primary LanguageJavaScriptMIT LicenseMIT

Do you have $ref's ?

Build Status NPM version Coverage Status

A simple way for solving $ref values:

var deref = require('deref');

Schema dereferencing

$ = deref();

var a = {
  id: 'a',
  type: 'object',
  properties: {
    b: {
      $ref: 'b'
    }
  }
};

var b = {
  id: 'b',
  type: 'string'
};

var c = {
  id: 'c',
  type: 'array',
  items: {
    $ref: 'a'
  }
};

console.log($(c, [b, a]).id);
// output: http://json-schema.org/c#

console.log($(c, [b, a], true).items.properties.b.type);
// output: string

Schema normalization

var schema = {
  id: 'http://x.y.z/rootschema.json#',
  schema1: {
    id: '#foo'
  },
  schema2: {
    id: 'otherschema.json',
    nested: {
      id: '#bar'
    },
    alsonested: {
      id: 't/inner.json#a'
    }
  },
  schema3: {
    id: 'some://where.else/completely#'
  }
};

console.log(deref.util.normalizeSchema(schema).schema2.nested.id);
// output: http://x.y.z/otherschema.json#bar

Schema identity

Since 0.3.0 the schema id will always be normalized internally to # when it's not provided.

This way the passed schema can be self-referenced using $ref's which is the expected behavior.

I know the id keyword is not required but while #/ is a self-reference we can assume # as the schema-id.

deref use that id for store and find $ref's, even self-references.

Without it is complex determine what to resolve. 🍻

Basic usage

The resulting function of calling deref() can accept three arguments:

  • fakeroot (string)

    Used on missing $schema values for resolve into fully qualified URIs.

    console.log($('http://example.com', { id: '#foo' }).id);
    // output: http://example.com#foo

    If missing will use http://json-schema.org/schema.

  • schema (object)

    The JSON-Schema object for dereferencing.

  • refs (array)

    Any additional schemas used while dereferencing.

    Since 0.2.4 passing an object is not longer supported.

  • ex (boolean)

    Whether do full dereferencing or not, false by default.

    Since 0.6.0 all inner references are not dereferenced by default.

    All other references are always dereferenced regardless the value of ex.

Examples

$('http://example.com', schema, true);
$(schema, refs, true);
$(schema, true);

Utilities

Aside the basics of $, this function will include:

  • $.refs (object)

    An registry of dereferenced schemas.

  • $.util (object)

    Exposes the internal helpers used by deref.

    • isURL(path)
    • parseURI(href)
    • resolveURL(base, href)
    • getDocumentURI(path)
    • findByRef(uri, refs)
    • resolveSchema(schema, refs)
    • normalizeSchema(fakeroot, schema)

Any refs passed MUST be an object of normalized schemas.

Note that calling $(schema) will not read/download any local/remote files.

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