# The small global helpers: MAIN, REPO, FUNC, NOW, CLONE, COPY, QUERIFY and PROMISIFY

> Use application globals, dates, deep copies, query strings and promise helpers.

Framework: total5
Product: Total.js 5 (total5@0.0.19)
Language: en
Content-SHA256: fe1db1d0b9705cf0ab8ab5aae2d10d62c6f0ca3c79286a1c96bcb884b0dc7f02
Snapshot: c0700e321579725c5cf4f5ace1ad7d2866d1b4f93c24a63c0b41b6b7998e976c
Sources: total5-installed@total5@0.0.19
Review: not-recorded

`total5` creates a few global objects for your own use and a few helpers that save a line of code. Nothing here needs setup.

- `MAIN`, `REPO` and `FUNC` are empty objects that the framework creates once: keep application data in `MAIN`, other data in `REPO` and your own functions in `FUNC`. `TEMP` is an object for temporary data that the framework replaces from time to time, so do not keep anything in it that you need later.
- `NOW` is the current date as a `Date`. It is refreshed about once a minute (and by some calls), so use `new Date()` when you need the exact time.
- `EMPTYARRAY` and `EMPTYOBJECT` are frozen empty values to return instead of creating new ones: they cannot be changed.
- `MODS` and `PLUGINS` are objects with the loaded modules and plugins by id. `F` and `Total` are the same object, the framework, and `print` is `console.log`. `NOOP` is a function that does nothing.
- `REQUIRE(name)` is `require` that also resolves packages from the `node_modules` of the application and accepts names such as `node:path`.
- `CLONE(value)` makes a deep copy: nested objects, arrays and dates are copied. `COPY(from, to)` copies the properties of the first object into the second and returns the second.
- `QUERIFY([url], object)` builds a query string from an object: empty values and `null` are skipped and an array becomes a comma separated value. With an url it returns `url?...`, without one it returns `?...`.
- `PROMISIFY(fn, a, b, c)` calls `fn(a, b, c, callback)` and returns a promise that resolves with the response of the callback or rejects with its error.

```js controllers/helpers.js
MAIN.started = 'yes';
REPO.counter = 1;
FUNC.double = n => n * 2;

exports.install = function() {
	ROUTE('GET /helpers/', helpers);
	ROUTE('GET /promisify/', promisify);
};

function helpers($) {

	const source = { a: 1, nested: { b: [1, 2] }, date: new Date(2026, 0, 5) };
	const cloned = CLONE(source);
	const target = { x: 1 };
	const returned = COPY({ y: 2 }, target);

	$.json({
		shared: [MAIN.started, REPO.counter, FUNC.double(4), typeof TEMP],
		now: [NOW instanceof Date, Math.abs(Date.now() - NOW.getTime()) < 120000],
		emptyarray: [EMPTYARRAY.length, Object.isFrozen(EMPTYARRAY)],
		emptyobject: [Object.keys(EMPTYOBJECT).length, Object.isFrozen(EMPTYOBJECT)],
		registries: [typeof MODS, typeof PLUGINS],
		same: [F === Total, typeof print, NOOP() === undefined],
		require: typeof REQUIRE('node:path').join,
		clone: [cloned !== source, cloned.nested !== source.nested, cloned.nested.b !== source.nested.b, cloned.date instanceof Date, cloned.nested.b.join()],
		copy: [returned === target, target.x, target.y],
		querify: QUERIFY('/search/', { q: 'a b', page: 2, empty: '', nothing: null, list: [1, 2] }),
		querify2: QUERIFY({ q: 'x' })
	});
}

async function promisify($) {

	const add = (a, b, callback) => setImmediate(callback, null, a + b);
	const fail = (callback) => setImmediate(callback, 'It failed');

	const sum = await PROMISIFY(add, 2, 3);
	let error = null;

	try {
		await PROMISIFY(fail);
	} catch (e) {
		error = e.message || String(e);
	}

	$.json({ sum: sum, error: error });
}
```