First using of fp-ts

first.ts

import {fold, Monoid} from "fp-ts/Monoid";

const enum EventProperties {
    eventLabel = 'eventLabel',
    eventContext = 'eventContext',
    eventContent = 'eventContent',
    eventLocation = 'eventLocation'
}

type EventAttributes = {
    [EventProperties.eventLabel]: string,
    [EventProperties.eventContent]: string,
    [EventProperties.eventContext]: string,
    [EventProperties.eventLocation]: string
};

const eventAttributesPropertyMonoid: Monoid<string> = {
    empty: '',
    concat: (x, y) => {
        return x.length ? x : y;
    }
};

const concatEventAttributesProperties = (x: string, y: string): string => eventAttributesPropertyMonoid.concat(x, y);

const eventAttributesMonoid: Monoid<EventAttributes> = {
    empty: {
        eventLabel: '',
        eventContent: '',
        eventContext: '',
        eventLocation: '',
    },
    concat: (x, y) => {
        return {
            eventLabel: concatEventAttributesProperties(x.eventLabel, y.eventLabel),
            eventContent: concatEventAttributesProperties(x.eventContent, y.eventContent),
            eventContext: concatEventAttributesProperties(x.eventContext, y.eventContext),
            eventLocation: concatEventAttributesProperties(x.eventLocation, y.eventLocation),
        };
    }
};

const data: Array<EventAttributes> = [
    {
        eventLabel: '',
        eventContent: 'b',
        eventContext: '',
        eventLocation: ''
    },
    {
        eventLabel: 'a',
        eventContent: 'b',
        eventContext: 'c',
        eventLocation: ''
    },
    {
        eventLabel: '',
        eventContent: '',
        eventContext: '',
        eventLocation: ''
    },
    {
        eventLabel: 'a1',
        eventContent: '',
        eventContext: '',
        eventLocation: ''
    }
];

const result = fold(eventAttributesMonoid)(data);

console.log(result);

second.ts

import {fold, getStructMonoid, Monoid} from "fp-ts/Monoid";

const enum EventProperties {
    eventLabel = 'eventLabel',
    eventContext = 'eventContext',
    eventContent = 'eventContent',
    eventLocation = 'eventLocation'
}

type EventAttributes = {
    [EventProperties.eventLabel]: string,
    [EventProperties.eventContent]: string,
    [EventProperties.eventContext]: string,
    [EventProperties.eventLocation]: string
};

const eventAttributesPropertyMonoid: Monoid<string> = {
    empty: '',
    concat: (x, y) => {
        return x.length ? x : y;
    }
};

const eventAttributesMonoid = getStructMonoid<EventAttributes>({
    eventLabel: eventAttributesPropertyMonoid,
    eventContent: eventAttributesPropertyMonoid,
    eventContext: eventAttributesPropertyMonoid,
    eventLocation: eventAttributesPropertyMonoid,
});

const data: Array<EventAttributes> = [
    {
        eventLabel: '',
        eventContent: 'b',
        eventContext: '',
        eventLocation: ''
    },
    {
        eventLabel: 'a',
        eventContent: 'b',
        eventContext: 'c',
        eventLocation: ''
    },
    {
        eventLabel: '',
        eventContent: '',
        eventContext: '',
        eventLocation: ''
    },
    {
        eventLabel: 'a1',
        eventContent: '',
        eventContext: '',
        eventLocation: ''
    }
];

const result = fold(eventAttributesMonoid)(data);

console.log(result);