arrange-act-assert/lib/monad/monad.js

The lightweight "Act-Arrange-Assert" oriented testing framework

"use strict";
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var __setModuleDefault = (this && this.__setModuleDefault) || (Object.create ? (function(o, v) {
    Object.defineProperty(o, "default", { enumerable: true, value: v });
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});
var __importStar = (this && this.__importStar) || (function () {
    var ownKeys = function(o) {
        ownKeys = Object.getOwnPropertyNames || function (o) {
            var ar = [];
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})();
Object.defineProperty(exports, "__esModule", { value: true });
exports.monad = monad;
const Assert = __importStar(require("assert"));
function monadify(res) {
    return {
        unwrap() {
            if ("ok" in res) {
                return res.ok;
            }
            else {
                throw res.error;
            }
        },
        match(match) {
            if ("ok" in res) {
                match.ok(res.ok);
            }
            else {
                match.error(res.error);
            }
        },
        should: {
            ok(value) {
                if ("ok" in res) {
                    Assert.strictEqual(res.ok, value);
                }
                else {
                    throw new Error(`Monad has error: ${res.error}`);
                }
            },
            error(error) {
                if ("error" in res) {
                    Assert.throws(() => {
                        throw res.error;
                    }, error);
                }
                else {
                    throw new Error(`Monad is ok with value: ${res.ok}`);
                }
            }
        }
    };
}
function isThenable(obj) {
    return obj && typeof obj.then === "function";
}
function monad(cb) {
    try {
        const res = cb();
        if (isThenable(res)) {
            return new Promise(async (resolve) => {
                try {
                    resolve(monadify({
                        ok: await res
                    }));
                }
                catch (e) {
                    resolve(monadify({
                        error: e
                    }));
                }
            });
        }
        else {
            return monadify({
                ok: res
            });
        }
    }
    catch (e) {
        return monadify({
            error: e
        });
    }
}