Introduction

The sole purpose of this immutable record is to simply act as a class factory for immutable types. For this particular implementation, it piggybacks off of immer and adds a with method to the record class.

Installation

npm install simple-immutable-record

or

yarn add simple-immutable-record

Usage

interface TestDataInterface {
    testNumber: number;
    testString: string;
    optionalString?: string;
}

const defaultValues: TestDataInterface = {
    testNumber: 1,
    testString: 'test',
};

class TestClass extends ImmutableRecord<TestDataInterface>(defaultValues) {
    withTestNumber(testNumber: number) {
        return this.with({ testNumber });
    }
}

const value = new TestClass();
// { testNumber: 1, testString: 'test' }

const newValue = value.with({ testNumber: 2, optionalString: 'test-optional' });
// { testNumber: 2, testString: 'test', optionalString: 'test-optional' }

Processing Nested Classes

interface TestParentClassInterface {
    data: TestDataInterface;
}

class TestParentClass extends ImmutableRecord<TestParentClassInterface>(
    { data: new TestClass() },
    values => {
        let { data } = values;

        if (!(data instanceof TestClass)) {
            data = new TestClass(data);
        }

        return { ...values, data };
    }
) {}

const value = new TestParentClass({
    data: { testNumber, testString },
});
// value.data instanceof TestClass === true

const value = new TestParentClass().with({
    data: { testNumber, testString },
});
// value.data instanceof TestClass === true