test-fns/dist/usePrep.js

write usecase driven tests systematically for simpler, safer, and more readable code

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.usePrep = void 0;
const helpful_errors_1 = require("helpful-errors");
/**
 * .what = declare a resource to be prepared before tests
 * .why = simplifies devexp by letting you write `const thing = usePrep(...)`
 * .mode =
 *   - 'beforeAll': prepare once for all tests
 *   - 'beforeEach': prepare fresh for each test run
 */
const usePrep = (setup, options = { mode: 'beforeAll' }) => {
    // metaphor: "drawer" = proxy target, "toolbox" = real resolved resource
    const drawer = {}; // exposed object users access
    let toolbox; // holds the resolved result of setup()
    // declare proxy handler up front so we can mutate it
    const proxyHandler = {
        get(_, prop) {
            if (toolbox === undefined)
                throw new helpful_errors_1.UnexpectedCodePathError('usePrep: tried to access value before setup completed');
            return toolbox[prop];
        },
        ownKeys() {
            return Reflect.ownKeys(drawer);
        },
        getOwnPropertyDescriptor(_, prop) {
            return Object.getOwnPropertyDescriptor(drawer, prop);
        },
        apply() {
            throw new Error('usePrep: value is not callable');
        },
    };
    const register = options.mode === 'beforeEach' ? beforeEach : beforeAll;
    register(async () => {
        toolbox = await setup();
        // assign properties from toolbox to drawer so Object.keys(), for..in, etc work
        Object.assign(drawer, toolbox);
        // remove get trap once setup is complete — access becomes direct
        delete proxyHandler.get;
    });
    // return a proxy that looks and feels like toolbox
    return new Proxy(drawer, proxyHandler);
};
exports.usePrep = usePrep;
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