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Marko Denic
Marko Denic

Posted on • Updated on • Originally published at

JavaScript Secrets

In this post I will share with you JavaScript tips you won’t find in most tutorials. Enjoy!

What is JavaScript?

JavaScript is a scripting language that enables you to create dynamically updating content, control multimedia, animate images, and so much more.

Let's jump to the tips!

* Shorten an array

You can set the length property to shorten an array.

Shorten an array

* Short-circuits conditionals

If you have to execute a function only if condition is true, you can use short-circuit.

Short circuit conditionals

* Show specific console.table() columns

By default, console.table() lists all elements in each row. You can use the optional “columns” parameter to select a subset of columns to display:

Show specific console.table() columns

* Remove duplicate elements from the array:

Remove duplicate elements from the array

* Convert a string to number:

Convert a string to number

* Convert a number to string:

Convert a number to string

You can find more HTML/CSS/JS Tips here:

If you liked this article, be sure to ❤️ it.

This article is a repost from my blog. Find the original post here: JavaScript Tips.

Let's keep in touch:
Twitter: @denicmarko

Top comments (10)

dsbarnes profile image

Excellent tips. I remember learning how to short circuit through counting substrings of a string like so:

arr.forEach(e => obj[e] = (ojb[e] || 0) + 1));

Changed my life.

Never knew about console.table(), that is just awesome.
Appreciate you sharing

denicmarko profile image
Marko Denic

Hey @dsbarnes , thanks for reading and taking the time to comment. Glad you like it.

stojakovic99 profile image
Nikola Stojaković • Edited

Converting a string to a number with a plus sign is a hack and is therefore one of the things you shouldn't do in JavaScript (just like changing the length property of an array).

denicmarko profile image
Marko Denic

Hi Nikola, thanks for reading. Yes, these two are tricks definitely. But, I saw both on MDN docs and w3docs, so I would consider them a legit tricks. :)

How do you like the rest?

olgagnatenko profile image
Olga Gnatenko

What about explicit conversion from string to number: str => Number(str)? I think this one is clearer and easier to understand/note for other developers.

Thread Thread
abourass profile image
Antonio B.

parseInt(str, 10)

Thread Thread
denicmarko profile image
Marko Denic • Edited

Hi Olga. Hi Antonio.
Thanks for reading and taking the time to comment.

There is at least 10 different ways to convert a string to number. Maybe I create a dedicated post about this topic.

myzel394 profile image

Awesome! Has someone benchmarks for +str and parseInt(str)?

sergix profile image
Peyton McGinnis

I actually didn't know some of these. Some great tips!!

denicmarko profile image
Marko Denic

Thanks Peyton. Glad you like it. :)