@snipsonian/core/es/monads/maybe.js

Core/base reusable javascript code snippets

import isNull from '../is/isNull';
import isUndefined from '../is/isUndefined';
export class Maybe {
    constructor(value) {
        this.value = value;
    }
    static of(value) {
        return new Maybe(value);
    }
    static nothing() {
        return new Maybe(null);
    }
    isNothing() {
        return isNull(this.value) || isUndefined(this.value);
    }
    map(mapper) {
        return this.isNothing()
            ? Maybe.nothing()
            : Maybe.of(mapper(this.value));
    }
    flatMap(mapper) {
        return this.isNothing()
            ? Maybe.nothing()
            : mapper(this.value);
    }
    getOrElse(elseValue) {
        return this.isNothing()
            ? elseValue
            : this.value;
    }
    getOrNull() {
        return this.getOrElse(null);
    }
    getOrEmptyArray() {
        return this.getOrElse([]);
    }
    getOrEmptyObject() {
        return this.getOrElse({});
    }
}