@mvst/ts-unions/dist/maybe.js

TypeScript union types for Maybe and RemoteData with pattern matching

import { curry } from "./utils.js";
function nothing() {
    return { type: "Nothing" };
}
function just(value) {
    return { type: "Just", value };
}
function isJust(maybe) {
    return maybe.type === "Just";
}
function isNothing(maybe) {
    return maybe.type === "Nothing";
}
const withDefault = curry(function withDefault(defaultValue, maybe) {
    return isJust(maybe) ? maybe.value : defaultValue;
});
const when = curry(function when(pattern, maybe) {
    const { nothing, just, _ = Function.prototype } = pattern;
    switch (maybe.type) {
        case "Nothing":
            return typeof nothing === "function" ? nothing() : _();
        case "Just":
            return typeof just === "function" ? just(maybe.value) : _();
    }
});
const map = curry(function map(fn, maybe) {
    return isJust(maybe) ? just(fn(maybe.value)) : maybe;
});
const andThen = curry(function andThen(fn, maybe) {
    return isJust(maybe) ? fn(maybe.value) : maybe;
});
export { andThen, isJust, isNothing, just, map, nothing, when, withDefault };