Schema definition

• Validating primitive data (strings & numbers)
• Validating Hash table (Object) structures
• Validating Arrays
• Defining required data
• Error messages TODO
• Conditional data validation TODO

Please look at the full list of Assertions and their options.

var inspector = require('json-inspector');

Primitive data validation

//validator definition
var validator = inspector.define('stirng-validator', {
    $is: String,
    $hasLengthOf: {min: 1, max: 255}
});

validator.validate('this is valid string');
console.log(validator.success); //true

validator.validate('');
console.log(validator.success); //false
console.log(validator.error); //ValidationError

Hash table (Object) data validation

//validator definition
var validator = inspector.define('user', {
    username: {
        $isAlphanumeric: 'en-US',
        $hasLengthOf: {min:1, max: 32}
    },
    email: {
        $isEmail: null //if you dont want to pass options object to $isEmail assertion, you can provide null value (even `undefined` would work). In the case, default options will be applied
    },
    address: {
        country_code: {
            $isAlpha: 'en-US'
            $hasLengthOf: {min: 2, max: 2}
        },
        street: {
            $is: String,
            $hasLengthOf: {max: 125}
        },
        zip: {
            $isInt: null, //again, null value means that no options for the $isInt assertion are specified. Default options will be applied
        }
    }
});

validator.validate({
    username: 'happie',
    email: 'test@test.com',
    address: {
        country: 'US',
        street: 'Second',
        zip: 96701
    }
});
console.log(validator.success); //true

Array data validation

//validator definition
var validator = inspector.define('cart', {
    items: {
        $forEach: { // each item of the array must pass following validation rules
            id: {
                $isInt: {min:1}
            },
            name: {
                $is: String
            }
        },
        $hasLengthOf: {max: 5} // `items` collection can have maximum of 5 items, no more
    }
});

validator.validate({
    items: [
        {
            id: 1,
            name: 'Supper-looking T-shirt'
        },
        {
            id: 29,
            name: 'Supper-looking Jumper'
        }
    ]
});
console.log(validator.success); //true

Specifying required properties

By default all properties are optional. That means if you don't provide any data, the validation process will pass.
You can specify which properties are required in validator schema definition or by setting all properties to required by default (see Validator options)

null values are treated as any other value by default - they are not threated as "empty" value by default. The means if a property can have null value, you can specify that either by [OR condition] or by explicitly telling a validator that null values should be treated as "empty" value - as data would not be sent at all.

//validator definition
var validator = inspector.define('user', {
    username: {
        $isAlphanumeric: 'en-US',
        $hasLengthOf: {min:1, max: 32}
    },
    email: {
        $isEmail: {allow_display_name: true}
    }
});

validator.validate();
console.log(validator.success); //true - because `username` and `email` properties are not required by default neither is the data object value the `username`, `email` properties are at.

validator.validate({});
console.log(validator.success); //true - because `username` and `email` properties are not required by default

To specify required properties use $required: true option:

//validator definition
var validator = inspector.define('user', {
    $required: true, // all properties within the validated object are set to required (they inherit this special `$required` option)
    username: {
        $isAlphanumeric: 'en-US',
        $hasLengthOf: {min:1, max: 32}
    },
    email: {
        $isEmail: {allow_display_name: true}
    }
});

validator.validate({});
console.log(validator.success); //false

The above example of specifying one $required option that other properties inherit is same as defining $required option individualy. This is equivalent schema definition:

{
    username: {
        $required: true, // defining required properties individualy
        $isAlphanumeric: 'en-US',
        $hasLengthOf: {min:1, max: 32}
    },
    email: {
        $required: true,
        $isEmail: {allow_display_name: true}
    }
}

To futher explain inheritance concept, look at the following example of schema definition:

{
    $required: true,
    username: {
        $required: false, // overwrites inherited `$required: true` option
        $isAlphanumeric: 'en-US',
        $hasLengthOf: {min:1, max: 32}
    },
    email: {//email property has inherited the `$required: true` option
        $isEmail: {allow_display_name: true}
    }
}

Note: The same inheritance concept applies for the error messages definitions (the $message option).