oh-my-props v2.0.4

oh-my-props

Validate & transform your props by schema.

API

new OhMyProps(props_description)

Creates an OhMyProps instance.

const propsInstance = new OhMyProps({
    foo: {
        type: String,
        default: 'bar',
    },
    baz: {
        type: Number,
        validator: (value) => Number.isInteger(value),
    },
});

Every value of props_description is an Object describing a property. Possible options:

Class method transform(props)

Transforms an object props. Any properties not defined at new OhMyProps will be omitted.

Returns a tramsformed object or null if transformation or validation has failed.

propsInstance.transform({
    foo: 'hello world!',
    baz: 10,
    unknown_property: 42,
});
// => { foo: 'hello world!', baz: 10 }

propsInstance.transform({ baz: 10 });
// => { foo: 'bar', baz: 10 }

propsInstance.transform({
    foo: [ 1, 2, 3 ], // expected String, got Array -> fail
    baz: 12.34,       // validation error: Number.isInteger will return false
});
// => null

Class method isValid(props)

Returns true if props was succesfully transformed and validated.

propsInstance.isValid({
    foo: 'hello world!',
    baz: 10,
    unknown_property: 42,
});
// => true

Static method wrap(props_description, targetFunction)

Returns a function that will transform and validate properties and pass them to targetFunction if they are valid. If they are not, an error will be throwed.

const doubleNumber = OhMyProps.wrap(
    {
        num: {
            type: Number,
            type_cast: true,
            validator: (value) => value > 0 && Number.isInteger(value),
        },
    },
    ({ num }) => {
        return num * 2;
    },
);

doubleNumber({ num: 13 });
// => 26

doubleNumber({ num: '10' });
// => 20

doubleNumber({ num: 'hello' });
// => TypeError: Invalid props.

doubleNumber({ num: 1.234 });
// => TypeError: Invalid props.

doubleNumber();
// => TypeError: Invalid props.

Statiс method createType({ name, transformer, validator })

Creates a user-defined type with functions that transforms (casts) a value and validates it.

Returns an object that should be passed as type to property description.

// create a type
const BASE64_BUFFER = OhMyProps.createType({
    name: 'BASE64_BUFFER', // not necessary, but useful for logs
    transformer: (value) => Buffer.from(value, 'base64'),
    validator: (value) => Buffer.isBuffer(value),
});

// use that type at the instance
const anotherPropsInstance = new OhMyProps({
    payload: {
        type: BASE64_BUFFER,
        type_cast: true,
    },
});

// try to cast
anotherPropsInstance.transform({
    payload: 'aGVsbG8gd29ybGQ=',
});
// => { payload: <Buffer 68 65 6c 6c 6f 20 77 6f 72 6c 64> }

// it works with buffers too
anotherPropsInstance.transform({
    payload: Buffer.from([ 0xDE, 0xAD ]),
});
// => { payload: <Buffer de ad> }