onvalid.js 

 onvalid.js 0.2.0
 Copyright (c) 2010 Mark Doffman, Codethink Ltd
 Onvalid may be freely distributed under the MIT license.

(function () {

Onvalid is a tool for validating JSON objects. Schemas are written directly in Javascript. Schemas are built using properties, JSON values and functions that check whether a given JSON value is valid.

 var __ = Onvalid = require ('onvalid');

 var schema = {
     username: __.exists,
     status: __.exists,
     latitude: __.opt (__.and (__.gte(-90), __.lte(90))),
     longitude: __.opt (__.and (__.gte(-180), __.lte(180))),
     type: __in (['Registered', 'Unregistered'])    
 };

 var obj = JSON.parse ('{       \
     "username": "Frank",       \
     "status": "Out on patrol", \
     "latitude": "57",          \
     "type": "Registered"       \
 }');

 if (Onvalid.validate (obj, schema)) {
     console.log ('Success');
 }

Onvalid also produces error messages that indicate why a JSON object has failed to validate. The validate function optionally takes a function parameter that reports the error.

 var obj = JSON.parse ('{       \
     "username": "Frank",       \
     /* Status is missing */    \
     "latitude": "57",          \
     "type": "Registered"       \
 }');

 var err = "";
 if (Onvalid.validate (obj, schema, function (e){err=e;})) {
     console.log ('Success');
 } else {
     console.log (err);
 }

             		           
                               
                            
                                
               
When in the browser, export to the global object, otherwise export to a
CommonJs module.
             		                            
    if (typeof exports !== 'undefined') {
        Onvalid = exports;
    } else {
        Onvalid = this.Onvalid = {};
    }
    
    var Onvalid = exports;
    
    Onvalid.VERSION = '0.2.0';
             		           
                               
                            
                                
               
This module depends on Underscore.js. Get underscore from the global
object or import from a CommonJs module.
             		                            
    var _ = this._;
    if (!_ && (typeof require !== 'undefined')) _ = require ('underscore' )._;
    
             		           
                               
                            
                                
               
Schemas



A schema is defined using standard Javascript object. Properties
of this object can be one of the following.



    

  • Value Checks for equality between the value in the schema and th JSON object.
    • 

  • Regex Checks that the value in the JSON object matches the regex.
    • 

  • Object Assumed to be a child schema. The property of the JSON object
is validated against it.
    • 

  • Function A validator function takes the value of the JSON object and decides
whether it is valid.
    • 




Properties of the JSON object not present in the schema are ignored.
             		                            
    
             		           
                               
                            
                                
               
Checks if the given object matches the given schema.
             		                            
    Onvalid.validate = function (object, schema, errorReturn) {
        return Onvalid.schema (schema)(object, errorReturn);
    };
             		           
                               
                            
                                
               
Returns a validator function based on type of the schema property
             		                            
    var wrapper = function (validator) {
        if (_.isFunction (validator)) 
            return validator;           
     
        if (_.isRegExp (validator))
            return Onvalid.regex (validator);         
      
        if (_.isArray (validator) || _.isString (validator) || _.isNumber (validator))
            return Onvalid.eq (validator);
        
             		           
                               
                            
                                
               
Assume a JSON object
             		                            
        return Onvalid.schema (validator);
    };
             		           
                               
                            
                                
               
Validators



Validator functions take the property and return a Boolean depending on
whether the property is valid. Validator functions also optionally take
a function used to return any validator erorrs.
             		                            
             		           
                               
                            
                                
               
Takes a function with just one argument, the property to validate
as well as a message to return if validation fails.



Generates a validator function that uses the message for error reporting.
             		                            
    var ew = Onvalid.errWrapper = function (validator, message) {
        return function (property, errorReturn) {
            var result = validator (property);
            if (!result && errorReturn && message)
                errorReturn (message);
            return result;
        };
    };
    
             		           
                               
                            
                                
               
The following functions generate validator functions.
             		                            
             		           
                               
                            
                                
               
Base
             		                            
    
             		           
                               
                            
                                
               
Validates if the property matches the given schema
             		                            
    Onvalid.schema = function (v) {return function (property, errorReturn) {
        if (_.isUndefined (property)) return false;
        return _.every (_.keys(v), function (key) {
            var error = "";
            var result = wrapper (v[key]) (property[key], function (e) {error = e;});
            
            if (!result && errorReturn)
                errorReturn ('Property at ' + key + ' is not valid: ' + error);
            return result;
        });
    };};
    
             		           
                               
                            
                                
               
Regex
             		                            
    
             		           
                               
                            
                                
               
The property must match the given regex
             		                            
    Onvalid.regex = function (v) {return ew (function (property) {
        return v.test (property);
    }, 'must match regex ' + v);};
    
             		           
                               
                            
                                
               
Boolean operators
             		                            
    
             		           
                               
                            
                                
               
The property can match any of the provided validator functions or values
             		                            
    Onvalid.or = function (vs) {return ew (function (p) {
            return _.any (vs, function (v) {
                    return wrapper (v)(p);
                });

    }, 'must match at-least one of the constraints');};
    
             		           
                               
                            
                                
               
Validates only if the property matches all of the given validators functions
or values.
             		                            
    Onvalid.and = function (vs) {return function (property, errorReturn) {
        return _.every (vs, function (v, i) {
                var error = "";
                var result = wrapper (v)(property, function (e){error = e;});

                if (!result && errorReturn)
                    errorReturn ('constraint at position ' + (i+1) + ' is not met: ' + error);

                return result;
            });
    };};
             		           
                               
                            
                                
               
Validates only if the property does not match any of the given validator
functions or values.
             		                            
    Onvalid.nor = function (vs) {return function (property, errorReturn) {
        return _.every (vs, function (v, i) {
                var result = wrapper (v)(property);
                
                if (result && errorReturn)
                    errorReturn ('constraint at position ' + (i+1) + ' must not be met');
                
                return !result;
            });
    };};
    
             		           
                               
                            
                                
               
Existential operators
             		                            
    
             		           
                               
                            
                                
               
The property is optional. It must match the provided validator function
or value only if it exists.
             		                            
    Onvalid.opt = function (v) {return function (property, errorReturn) {
        if (_.isUndefined (property))
            return true;
        else
            return wrapper (v) (property, errorReturn);
    };};
     
             		           
                               
                            
                                
               
Ensure that the property does not exist.
             		                            
    Onvalid.notExists = ew (function (p) {
        return _.isUndefined(p);
    }, 'must not exist');
    
             		           
                               
                            
                                
               
Ensure that the property exists.
             		                            
    Onvalid.exists = ew (function (p) {
        return !_.isUndefined(p);
    }, 'must exist');
    
             		           
                               
                            
                                
               
Array operators
             		                            
    
             		           
                               
                            
                                
               
Ensure that all items in the property array are present in the schema
array.
             		                            
    Onvalid.all = function (vs) {return ew (function (ps) {
        if (!_.isArray(ps)) return false;
        return _.every (ps, function (p) {return _.contains(p, vs);});
    }, 'must match all of ' + vs);};
    
             		           
                               
                            
                                
               
Ensure that the property is contained in the collection provided.
             		                            
    Onvalid._in = function (vs) {return ew (function (p) {
        return _.contains(p, vs);
    }, 'must be contained in ' + vs);};
    
             		           
                               
                            
                                
               
Ensure that the property is not contained in the colleciton provided.
             		                            
    Onvalid.nin = function (vs) {return ew (function (p) {
        return _.every (vs, function (v) {return !_.isEqual (p, v);});
    }, 'must not be contained in' + vs);};
    
             		           
                               
                            
                                
               
Comparison operators
             		                            
    
             		           
                               
                            
                                
               
Ensure that the property is equal to the value provided.
             		                            
    Onvalid.eq = function (v) {return ew (function (p) {
        return _.isEqual(p, v);
    }, 'must be equal to ' + v);};
    
             		           
                               
                            
                                
               
Ensure that the property is not equal to the value provided.
             		                            
    Onvalid.ne = function (v) {return ew (function (p) {
        return !_.isEqual(p, v);
    }, 'must not be equal to ' + v);};
    
             		           
                               
                            
                                
               
Ensure that the property wholely divisible by the value provided.
             		                            
    Onvalid.mod = function (v) {return ew (function (p) {
        return (p % v) === 0;
    }, 'must be wholely divisible by ' + v);};
             		           
                               
                            
                                
               
Ensure that the property is greater than the value provided.
             		                            
    Onvalid.gt = function (v) {return ew (function (p) {
        return p > v;
    }, 'must be greater than ' + v);};
    
             		           
                               
                            
                                
               
Ensure that the property is less than the value provided.
             		                            
    Onvalid.lt = function (v) {return ew (function (p) {
        return p < v;
    }, 'must be less than ' + v);};
    
             		           
                               
                            
                                
               
Ensure that the property is greater than or equal to the value provided.
             		                            
    Onvalid.gte = function (v) {return ew (function (p) {
        return p >= v;
    }, 'must be greater than or equal to ' + v);};
    
             		           
                               
                            
                                
               
Ensure that the property is less than or equal to the value provided.
             		                            
    Onvalid.lte = function (v) {return ew(function (p) {
        return p <= v;
    }, 'must be less than or equal to ' + v);};

})();