JavaScript Utilities

These are some JavaScript utilities I use in different projects. If you want to use them as well, you're most welcome. You can install the package with:

npm install @noeldemartin/utils

Helpers

There is a bunch of helpers I've been reusing across projects, and I wanted to get them in one place to abide by the DRY principle (Don't Repeat Yourself). They consist of simple operations such as converting a string to camelCase, checking if an element exists within an array, etc.

The best way to check these out is by looking at the test files within the src/helpers/ folder.

MagicObject

One particularly interesting helper is MagicObject. I've found myself using this pattern ever more often, so I encapsulated it in this class. The idea is that taking advantage of Proxy objects, and a using an obscure property of JavaScript constructors, we can use PHP's Magic Methods in JavaScript:

class MyClass extends MagicObject {

    protected __get(property: string) {
        if (property === 'foo') {
            return 'Foo works!';
        }

        return undefined;
    }

}

const myObject = new MyClass();

console.log(myObject.foo); // prints "Foo works!"
console.log(myObject.bar); // prints undefined

Take a look at the source code and tests if you're interested to learn more!

Fluent API

I strive to write readable code, and I wasn't happy with combining my own helpers with built-in methods. There is nothing in the fluent API that's not implemented in some helper, this is all about readability.

For example, this is the kind of code I'd write often:

const items = ['my', 'array', 'of', 'cool', 'array', 'items'];

return arrayUnique(items.filter(item => item.startsWith('a')));

Where arrayUnique is a custom helper (which you can find in this package), and Array.filter is a native method. My only option was to combine method chaining with nesting function calls. And the end result wasn't too readable.

Now, with the fluent API I created in this package, I can write it like this:

return fluent(['my', 'array', 'of', 'cool', 'array', 'items']) // or, to be explicit, arr([...])
    .filter(item => item.startsWith('a'))
    .unique()
    .toArray(); // returns ['array']

Like this, I'm able to combine native methods with custom helpers using method chaining.

And that's not only with arrays, for example with strings I can do:

return fluent('foo-bar') // or, to be explicit, str('...')
    .replace('foo', 'hello')
    .replace('bar', 'world')
    .toStudlyCase()
    .toString(); // returns "HelloWorld"

And all of this works properly with TypeScript! So when I create a variable with fluent('foo'), I get auto-completion for both my custom helpers and native methods - along the complete method chain!

tap

I also included my own port of Laravel's tap helper. This allows me to rewrite this kind of code:

const foo = new Foo();

foo.bar = 'bar';

return foo;

Like this:

return tap(new Foo(), foo => {
    foo.bar = 'bar';
});

facade

Something else Laravel-inspired are facades. Unlike Laravel, there is no underlying service container, these facades just hold static proxies to an instance:

// UsersService.ts
export default class UsersService {

    async all() {
        const response = await fetch('/users');
        const json = await response.json();

        return json.map(userJson => User.fromJson(userJson));
    }

}

// Users.ts
import UsersService from './UsersService';

export default facade(new UsersService());

// Anywhere in your app...
import Users from './Users';

const users = await Users.all();

// In your tests...
import Users from './Users';
import UsersServiceMock from './UsersServiceMock';

Users.setInstance(new UsersServiceMock());