index.js

/*
The MIT License (MIT)

Copyright (c) 2014 The Australian National University

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
*/

'use strict';


var checkNumber = function(schema, instance) {
  var errors = [];

  if (schema.maximum !== null) {
    if (instance > schema.maximum)
      errors.push('may be at most ' + schema.maximum);
    else if (schema.exclusiveMaximum && instance >= schema.maximum)
      errors.push('must be less than ' + schema.maximum);
  }
  if (schema.minimum !== null) {
    if (instance < schema.minimum)
      errors.push('must be at least ' + schema.minimum);
    else if (schema.exclusiveMinimum && instance <= schema.minimum)
      errors.push('must be more than ' + schema.minimum);
  }
  if (schema.multipleOf != null) {
    if ((instance / schema.multipleOf) % 1 != 0)
      errors.push('must be a multiple of ' + schema.multipleOf);
  }

  return errors;
};


var fieldErrors = function(errors) {
  if (errors.length > 0)
    return [ { path: [], errors: errors } ];
  else
    return [];
};


var validator = {};


validator.boolean = function(schema, instance) {
  var errors = [];

  if (typeof instance != 'boolean')
    errors.push('must be boolean');

  return fieldErrors(errors);
};


validator.enum = function(schema, instance) {
  var errors = [];

  if (schema.enum.indexOf(instance) < 0)
    errors.push('value not in list');

  return fieldErrors(errors);
};


validator.number = function(schema, instance) {
  var errors = [];

  if (typeof instance != 'number')
    errors.push('must be a number');
  else
    errors = checkNumber(schema, instance);

  return fieldErrors(errors);
};


validator.integer = function(schema, instance) {
  var errors = [];

  if (typeof instance != 'number')
    errors.push('must be a number');
  else {
    errors = checkNumber(schema, instance);
    if (instance % 1 > 0)
      errors.unshift('must be an integer');
  }

  return fieldErrors(errors);
};


validator.string = function(schema, instance) {
  var errors = [];

  if (typeof instance != 'string')
    errors.push('must be a string');
  else {
    if (schema.maxLength != null && instance.length > schema.maxLength)
      errors.push('may have at most ' + schema.maxLength + ' characters');
    if (schema.minLength != null && instance.length < schema.minLength)
      errors.push('must have at least ' + schema.minLength + ' characters');
    if (schema.pattern != null && !(RegExp(schema.pattern).test(instance)))
      errors.push('must match ' + schema.pattern);
  }

  return fieldErrors(errors);
};


validator.array = function(schema, instance, context) {
  var errors = [];
  var result, i, j;

  if (!Array.isArray(instance))
    return fieldErrors(['must be an array']);
  else {
    if (schema.maxItems != null && instance.length > schema.maxItems)
      errors.push('may have at most ' + schema.maxItems + ' items');
    if (schema.minItems != null && instance.length < schema.minItems)
      errors.push('must have at least ' + schema.minItems + ' items');
    result = fieldErrors(errors);

    if (schema.items != null) {
      for (i in instance) {
        errors = validate(schema.items, instance[i], context);
        for (j in errors) {
          result.push({
            path  : [i].concat(errors[j].path),
            errors: errors[j].errors
          });
        }
      }
    }
  }

  return result;
};


var requires = function(schema, key) {
  var subschema;

  if (schema.required != null && schema.required.indexOf(key) >= 0)
    return 'must be present';
  else {
    subschema = schema.properties[key];
    if (subschema.type == 'array' && subschema.minItems > 0)
      return 'must have at least ' + subschema.minItems + ' items';
    else
      return null;
  }
};

validator.object = function(schema, instance, context) {
  var result = [];
  var key, errors, i;

  if (instance == null)
    instance = {};

  if (instance.constructor !== Object)
    result.push({ path: [], errors: ['must be a plain object'] });
  else {
    for (key in schema.properties) {
      if (instance.hasOwnProperty(key)) {
        errors = validate(schema.properties[key], instance[key], context);
        for (i = 0; i < errors.length; ++i)
          result.push({
            path  : [key].concat(errors[i].path),
            errors: errors[i].errors
          });
      }
      else if (requires(schema, key)) {
        result.push({
          path  : [key],
          errors: [requires(schema, key)]
        });
      }
    }
  }

  return result;
};


var merge = function() {
  var args = [].slice.call(arguments);
  var result = args.every(Array.isArray) ? [] : {};
  var i, obj, key;
  for (i in args) {
    obj = args[i];
    for (key in obj)
      result[key] = obj[key];
  }
  return result;
};


var without = function(obj) {
  var args = [].slice.call(arguments);
  var result = Array.isArray(obj) ? [] : {};

  for (var key in obj)
    if (args.indexOf(key) < 0)
      result[key] = obj[key];

  return result;
};


var getIn = function(root, path) {
  if (path.length == 0 || root == undefined)
    return root;
  else
    return getIn(root[path[0]], path.slice(1))
};


var cat = function(arrayOfArrays) {
  return [].concat.apply([], arrayOfArrays);
};


var resolve = function(schema, context) {
  var reference = schema['$ref'];

  if (reference) {
    if (!reference.match(/^#(\/([a-zA-Z_][a-zA-Z_0-9]*|[0-9]+))*$/))
      throw new Error('reference '+reference+' has unsupported format');

    return {
      allOf: [
        without(schema, '$ref'),
        getIn(context, reference.split('/').slice(1))
      ]
    };
  } else
    return schema;
};


var validate = function(schema, instance, context) {
  var effectiveContext = context || schema;
  var effectiveSchema  = resolve(schema, effectiveContext);

  if (effectiveSchema.allOf) {
    var results = [without(effectiveSchema, 'allOf')]
      .concat(effectiveSchema.allOf)
      .map(function(schema) {
        return validate(schema, instance, effectiveContext);
      });
    return cat(results);
  } else {
    var type = effectiveSchema.enum ? 'enum' : effectiveSchema.type;
    if (type)
      return validator[type](effectiveSchema, instance, effectiveContext);
    else
      return [];
  }
};

module.exports = validate;