@alexspirgel/schema NPM

Schema

Schema is a JavaScript validator, meaning it will detect if an input matches defined constraints, it will not edit input data. This was originally developed for validating complex options objects as they are passed into other scripts, but it can be used effectively outside of that specific example.

Installation

Using NPM:

npm install @alexspirgel/schema

const Schema = require('@alexspirgel/schema');

Using a script tag:

Download the normal or minified script from the /dist folder.

<script src="path/to/schema.js"></script>

Usage

Create a schema using a model:

const schema = new Schema({
    type: 'number',
    greaterThan: 5
});

Use the schema to validate an input:

schema.validate(6); // returns true

You can specify an error style as the second parameter of the validate method. The error style options are:

'throw' (default) will throw a formatted error on validate failure. The message will include multiple errors when applicable.
'array' will return an array of errors on validate failure. Useful for sorting through multiple errors programatically.
'boolean' will return false on validate failure.

schema.validate(4); // throws an error
schema.validate(4, 'throw'); // throws an error
schema.validate(4, 'array'); // returns an array
schema.validate(4, 'boolean'); // returns false

More complex example:

const schema = new Schema({
    required: true,
    type: 'object',
    propertySchema: {
        width: {
            required: true,
            type: 'number',
            greaterThanOrEqualTo: 0
        },
        tags: {
            type: 'array',
            itemSchema: [
                {
                    type: 'number'
                },
                {
                    type: 'string'
                }
            ]
        }
    }
});
schema.validate(null); // fail
schema.validate({}); // fail
schema.validate({ // pass
    width: 10
});
schema.validate({ // fail
    width: -5
});
schema.validate({ // pass
    width: 10,
    tags: []
});
schema.validate({ // fail
    width: 10,
    tags: ['test', true]
});
schema.validate({ // pass
    width: 10,
    tags: ['test', 123, 'hello']
});

Model Properties

These parameters are used to define the schema rule set.

This property has no restrictions on what models it can belong to.

Available values: any boolean.

Setting required to true requires an input not to be null or undefined.

Setting required to false or omitting it from the model (equivalent to undefined) will not require any input. If an input is null or undefined all other model properties will be skipped and the input is valid.

model = {
  required: true
};

This property has no restrictions on what models it can belong to.

Available values: boolean, number, string, array, object, function.

An input must match the set type.

model = {
  type: 'boolean'
};

Notes:

NaN is not a valid number.
null is not a valid object.
Arrays are not objects and objects are not arrays.
- [] is not a valid object.
- {} is not a valid array.

This property is restricted to models with a type property of boolean, number, or string.

Available values: any value or array of values.

An input must match the value or one of the values in an array of values.

model = {
  type: 'string',
  exactValue: 'hello world'
};

model = {
  type: 'number',
  exactValue: [5, 7, -12]
};