maybe-monade/dist/MaybeCallback.js

Maybe monad implementation in Typescript

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
var maybe_1 = require("./maybe");
var utils_1 = require("./utils");
var MaybeCallback = /** @class */ (function () {
    function MaybeCallback(callback) {
        this.callback = callback;
    }
    /**
     * return an instance of Maybe wrapping an empty value
     */
    MaybeCallback.none = function () {
        return new MaybeCallback(null);
    };
    /**
     * if the provided callback is not a function, return an instance of Maybe wrapping a nonempty value,
     * otherwise throw an error
     * @param callback
     */
    MaybeCallback.some = function (callback) {
        if (typeof callback !== "function") {
            throw new Error(utils_1.ErrorMessages.emptyCallback);
        }
        return new MaybeCallback(callback);
    };
    /**
     * return true if the wrapped value is empty, false otherwise
     */
    MaybeCallback.prototype.isEmpty = function () {
        return this.callback === null;
    };
    /**
     * Call the wrapped function in unsafe mode (could throw errors)
     * if the wrapped function is empty return empty Maybe,
     * otherwise return an instance of Maybe wrapping the function result
     * @param args : arguments to pass to the wrapped function
     */
    MaybeCallback.prototype.apply = function () {
        var args = [];
        for (var _i = 0; _i < arguments.length; _i++) {
            args[_i] = arguments[_i];
        }
        if (!this.isEmpty() && typeof this.callback === "function") {
            return maybe_1.Maybe.fromValue(this.callback.apply(null, args));
        }
        else {
            return maybe_1.Maybe.none();
        }
    };
    /**
     * call the wrapped function in a safe mode,
     * wrap the execution in a try catch bloc. in case of error return empty Maybe,
     * otherwise return an instance of Maybe wrapping the function result
     * @param args : arguments to pass to the wrapped function
     */
    MaybeCallback.prototype.applySafe = function () {
        var args = [];
        for (var _i = 0; _i < arguments.length; _i++) {
            args[_i] = arguments[_i];
        }
        if (this.isEmpty() || typeof this.callback !== "function") {
            return maybe_1.Maybe.none();
        }
        try {
            return maybe_1.Maybe.fromValue(this.callback.apply(null, args));
        }
        catch (ex) {
            return maybe_1.Maybe.none();
        }
    };
    return MaybeCallback;
}());
exports.MaybeCallback = MaybeCallback;