#json-schema-filter

Filters (removes) objects recursively from document based on passed json-schema

Note that this does NOT validate your document against the schema, use something like JSV npm after calling.

For performance reasons it is assumed that the json-schema contains less items then the document, that is you are going to be removing from the document in most or all cases, if not I would recommend another solution which bases its recursive evaluation on the document instead.

Install

$ npm install json-schema-filter

Usage...

var filter = require('json-schema-filter');

var schema = {
    "title": "Example Schema",
    "type": "object",
    "properties": {
      "firstName": {
        "type": "string"
      },
      "lastName": {
        "type": "string"
      },
      "age": {
        "description": "Age in years",
        "type": "integer",
        "minimum": 0
      },
      "general": {
        "type": "object",
        "required": false
      },
      "contacts": {
        "type": "array",
        "id": "http://jsonschema.net/contacts",
        "required": false,
        "items": {
          "type": "object",
          "id": "http://jsonschema.net/contacts/0",
          "required": false,
          "properties": {
            "phone": {
              "type": "string",
              "required": false
            }
          }
        }
      },
      "hobbies":{
        "type": "array",
        "required": false,
        "items": {
          "type": "string"
        }
      }
    },
    "required": ["firstName", "lastName"]
};

var document = {firstName: 'John', lastName: 'Dow!', shouldNot: 'see this!'};

var results = filter(schema, document);   

console.log(results);  // # {firstName: 'John', lastName: 'Dow!'}

// Works on nested objects and arrays as well...
var document2 = {
    firstName: 'Johnny',
    lastName: 'Dowsky',
    contacts: [
        {phone: '303943', shouldNot: 'see this!'},
        {phone: '399494'}
    ]
}
var nestedResults = filter(schema, document2);

console.log(nestedResults);  // # {firstName: 'Johnny', lastName: 'Dowski', contacts: [{phone: '303943', phone: '399494'}]}

Notes:

"object" without "properties" or free form objects

If a "type": "object" with no "property": is defined (see 'general:' in above example), or empty, the entire object is removed from the results. It could be that you require it to be included but empty, but to the best of my knowledge I thought it would be cleaner to simply remove it if empty. Else it copies everything over, as in all of what is in the properties of the key.

Background info: The lack of property is legal in json-schema and means anything goes, or what I refer to as free-form.. free-style.. oh well, pick your meaning for it, it has the word 'free'!