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Minhazur Rahman Ratul
Minhazur Rahman Ratul

Posted on • Updated on

5 useful javascript tricks for begginers.

#javascript #webdev #codenewbie #tutorial

In this post, I will show you 5 awesome javascript tricks which will make your life more easier. And will help you to become a better developer. So if you are interested, continue reading.

Trick-1: Remove duplicates from an Array!

This trick is pretty simple. Suppose I have an array which is containing number, strings and booleans. And in this array I want to make sure, that there's no duplicate item. So how do you do do that?

const array = [1, 2, 3, 2, 1, true, true, false, 'Ratul', 1, 5];
const filtered__array = [...new Set(array)];
console.log(filtered__array) // [ 1, 2, 3, true, false, 'Ratul', 5 ]
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Simple!

Trick-2: Turn a Decimal Number to a integer.

This one is a pretty straight forward trick. Let me show you.

const number = 23.6565
console.log(number | 0);
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Isn't it so simple!

Trick-3: Getting the Last Value of an Array!

Suppose you have an array of something. Now if you want to have the last item of the array, how will you do that?

const array = [1, 2, 3, 4, 5]
const last_Item = array.slice(-1)
console.log(last_Item)
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Here we go! Now if you put -2 instead of -1, you will get the last two values of the array and then if you give -3 instead of -2, you will get the value of last three index's and so on.

Trick-4: Get a random index value from an array.

Suppose we are doing a lottery programme. We have an array which is containing the names of the prticipants. Now we want only one user randomly from the array to decide a winner.

const participants = ['Ratul', 'George', 'july', 'Padrik', 'G']
const winner = participants[Math.floor(Math.random() * participants.length)]
console.log(winner) // july was the winner 😊
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Trick-5: Detect the most lengthy word in an array

Create an array and add some different strings. Now print the most lengthy string of this array.

const array = ['Apple', 'Pine-apple', 'Banana', 'Jack-fruit']

let most_lengthy_string = ''
array.forEach((item) => {
  if (item.length > most_lengthy_string.length) {
    most_lengthy_string = item
  }
})
console.log(most_lengthy_string)
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Simple! So let me explain you what's going on here. Firstly we have array which is containing some strings. And After that, I have created a variable which is containing an empty string. And now, to detect the most lengthy string in this array, I need to take a look at all of the array items So I have looped through the array. And if the array's item length is greater that the length of our "most_lengthy_string" The we are reassigning the value of the variable and after all I am just printing out the variable. That's all!

Conclusion

Thanks for reading this article. Hope you enjoyed that. If you have any doubt regarding that post, please let me know. And make sure you follow me to recieve all the informational posts just like that.

:)

Top comments (27)

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danim47c profile image
Daniel Mateos •

I think the best way you can obtain the most lengthy string in an array is this:

const mostLengthy = someArray
    .reduce((acc, i) =>
        i.length > acc.length
             ? i
             : acc
)
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coderslang profile image
Coderslang: Become a Software Engineer •

That's a good one, although it might be useful to first filter out nulls and undefineds from the array:

const mostLengthy = someArray
    .filter(item => item)
    .reduce((acc, i) => i.length > acc.length ? i : acc);
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mdegoys profile image
Matthieu • • Edited

You can also do this way I believe (sort by the length of the words in descending order, then pick the first one).

const mostLengthy = someArray.sort((x, y) => y.length - x.length)[0]
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Maybe it's more understandable ? But I agree reduce is great :).

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developeratul profile image
Minhazur Rahman Ratul •

useful :)

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nibelune profile image
Benoît Schiex • • Edited

last_Item = arr.slice(-1) would not return the last item but a new array containing the last item.

you can do :

const lastItem = arr[arr.length-1]
const lastItem = arr.slice(-1)[0]
const lastItem = arr.slice(-1).pop()
const [lastItem] = arr.slice(-1)
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developeratul profile image
Minhazur Rahman Ratul •

wow nice. !

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jonrandy profile image
Jon Randy 🎖️ • 
const last_item = array.reverse()[0]
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kelsny profile image
Kelly •

that one mutates the array, though

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jonrandy profile image
Jon Randy 🎖️ •

Yeah. I always wondered why they decided to make it like that

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vbubblery profile image
Juncheng • • Edited

Try with this:

const number = 23.6565
console.log(~~number);
const string = "24"
console.log(+24)
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Sloan, the sloth mascot
Comment deleted
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nibelune profile image
Benoît Schiex •

This is a bitwise or.
Since bitwise operations only make sense on integers, the decimal part is truncated.

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captainofphb profile image
CaptainOfPhB •

I think those are basic skills of javascript developer(maybe you are a new bee), and the second trick is not recommended, Math.round/Math.floor/Math.ceil are better choice, which will make your code more readable.

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aspiiire profile image
Aspiiire •

That is really useful, thank you 😁

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baikai223 profile image
baikai223 •

获取数组的最后一项数据使用数组的api方法不是更好吗?arr.pop()

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developeratul profile image
Minhazur Rahman Ratul •

I don't understand what you have said :|

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baikai223 profile image
baikai223 •

Wouldn't it be better to use pop() instead of slice()?

Thread Thread
 
developeratul profile image
Minhazur Rahman Ratul •

you can use what ever you want. ......I know how to do that with slice so I have shown with slice. If you know how to do that with pop() you can use pop. :)

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coderdeepansh profile image
Deepansh Dash •

Thanks it is useful.

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ianwijma profile image
Ian Wijma •

Not 100% sure you should the weird int casting. Not everyone knows about it. And could cause confusion when reading it. Maybe just use parseInt. 😁 Really Cool post though!!

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