Dom (dcode)

Posted on Sep 15, 2022

7 Must Know JavaScript Tips & Tricks 🎈

#javascript #webdev #beginners #tutorial

Let's have a look at 7 valuable tips and tricks found in the most popular language in the world, JavaScript.

1. Destructuring with Parameters

You can use object destructuring within function parameters. A popular use case for this would be something like event listeners, and gaining access to the target property on the event object.

buttonElement.addEventListener("click", ({ target }) {
    // is the same as using e.target 👇
    console.log(target);
});

2. Deep Copy with JSON

You may have heard of using object spread or Object.assign() to make shallow copies of an object, but did you know about using JSON to make deep copies?

Simply convert an object to JSON using JSON.stringify() and then re-parse it using JSON.parse() to create a deep copy.

Just remember to only do this for simple objects, as doing it on large objects may raise performance issues.

const person = {
    name: "Dom",
    age: 28,
    skills: [
        "Programming",
        "Cooking",
        "Tennis"
    ]
};

const copied = JSON.parse(JSON.stringify(person));

// false 😎
console.log(person.skills === copied.skills);

3. Easy Defaults with OR

I talk about this one a lot. Basically, you can use the logical OR operator (||) for defaults as opposed to using an if statement.

Alternatively, for stricter comparisons, you can take advantage of the nullish coalescing operator

Old Code (using if statement - 4 lines)

let username = getUsername();

if (!username) {
    username = "Dom";
}

New Code (using || - 1 line)

const username = getUsername() || "Dom";

The new code also means you can use const over let.

4. Advanced Array Searching

Step aside, indexOf() and includes() because there's another method that allows for advanced array searching and it's called find().

The find() method allows you to pass in a test function. The first element within the array to pass the test function will be returned.

This makes for more useful array searching.

const occupations = [
    "Lawyer",
    "Doctor",
    "Programmer",
    "Chef",
    "Store Manager",
];

const result = occupations.find(o => o.startsWith("C"));

// "Chef" 🧑‍🍳
console.log(result);

5. Remove Array Duplicates

You may have heard of this one before, but there's a really simple way to remove duplicates from an array using the Set data structure.

Basically, Set doesn't allow duplicate values. We can take advantage of that by turning an array into a Set, and then back into an array.

const numbers = [5, 10, 5, 20];
const withoutDuplicates = Array.from(new Set(numbers));

// [5, 10, 20] 👇
console.log(withoutDuplicates);

6. Self-Invoking Functions

This one is a classic. Self-invoking functions are functions that execute themselves. A common use case for these is to assign a variable or constant that requires complex logic.

const someComplexValue = (() => {
    const a = 10;
    const b = 20;

    if (a > b) {
        return a * b;
    }

    return b / a;
})();

Of course, the above example is trivial but you can imagine the kind of complex code you may require to be within the self-invoking function.

7. Array Copying with Spread

Last on this list involves creating shallow copies of an array. We can do this using spread (...).

const numbers = [5, 19, 24, 36];
const numbersCopy = [...numbers];

// false
console.log(numbers === numbersCopy);

I hope you learnt at least something new from this list. For more JavaScript content, check out my YouTube channel, dcode.

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Top comments (12)

Thomas Bnt • Sep 15 '22

Nice !
You can put video embed with :

{% embed https://www.youtube.com/watch?v=oRekCcwSeXs %}

Matija Novosel • Sep 15 '22

Excellent post, though for number 5 I'd note that using Set does indeed remove duplicates but only if the array is filled with primitive values.

In the case of an array being filled with objects, however...

const departureTimes = [{"departureTime": "07:00:00"}, {"departureTime": "07:00:00"}, {"departureTime": "13:05:00" }];
const unique = Array.from(new Set(departureTimes)); // [{"departureTime":"07:00:00"},{"departureTime":"07:00:00"},{"departureTime":"13:05:00"}]

A little overkill but In this case something like this could also work:

const unique = Array.from(new Set(departureTimes.map(x => JSON.stringify(x)))).map(x => JSON.parse(x)); // [{"departureTime":"07:00:00"},{"departureTime":"13:05:00"}]

Orim Dominic Adah • Sep 19 '22

I don't see how 14 and 16 are 'jurassic' versions. 18 is the latest.
Thanks for the update though

Vinícius Hoyer • Sep 16 '22

That was exactly what I was going to comment, thanks

camiloforero • Sep 19 '22

In production environments, either Active LTS (16) or Maintenance LTS (14) should be used.

Node 18 is not an LTS at all, it's the Current release, and it is not quite fit for production use until the 25th of october, when it will become Active LTS

It's all here: github.com/nodejs/release#release-...