/javascript-array-from-applications/ about dmitripavlutin.com-comments HOT 18 OPEN

Comment written by guy on 08/27/2019 15:35:32

Uhm, a little slip here:
Array.from(new Set(['one', 'two'])); // => ['one', 'two', 'three']
Unless there's a new feature I'm unaware of :)

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Comment written by Dmitri Pavlutin on 08/27/2019 15:48:09

Nice catch! I will fix the example.

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Comment written by Joshua Baker on 08/28/2019 00:23:47

In 4.2, your example's lambda function is () => value, but value was not defined. Did you mean init?

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Comment written by Patrick John Haskins on 08/28/2019 06:52:29

I'm typing from my phone, so I can't test this to be sure, but I believe your deepCopy() in #3 will not perform a true deep copy. It will effectively deep copy multi-dimensional arrays of immutable values. When it encounters an object, though, it will only copy the reference to the object.

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Comment written by Dmitri Pavlutin on 08/28/2019 07:03:44

Yep, it will deep copy only the array objects.
I updated the text to be more clear.

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Comment written by Dmitri Pavlutin on 08/28/2019 07:03:51

Fixed.

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Comment written by Yevgen Gorbunkov on 08/28/2019 15:07:31

Wouldn't most of the above use cases be solved in a bit more concise manner with
spread operator (...)?

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Comment written by Dmitri Pavlutin on 08/28/2019 15:15:10

What exact use cases are you referring to? Please elaborate.

You can only use spread operator as an alternative of Array.from() to clone an array or to remove duplicates.

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Comment written by Yevgen Gorbunkov on 08/29/2019 15:44:38

Double object property values; Set/Map/NodeList into array; Shallow array copy; Fill array with values/objects; Range of numbers; Unique entries

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Comment written by Yevgen Gorbunkov on 08/30/2019 12:36:58

Check out this collection of codepens

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Comment written by Dmitri Pavlutin on 08/30/2019 13:31:58

Thanks for providing the demos. Sure, you can use spread operator as an alternative if you'd like.

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Comment written by Masha I. Klachko-Blair on 09/27/2019 19:15:27

To me, spread operators are super unreadable. Array.from() is much easier to read and understand.

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Comment written by Dmitri Pavlutin on 09/28/2019 14:04:28

It's a matter of taste. I'm ok with using the spread operator.
But I like to use Array.from() when I need the map function of it.

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Comment written by Waheed Afolabi on 10/07/2019 10:23:50

Nice article. It's really helpful.

Seems Array.from( ) clones an array including nested ones without using the recursiveClone() function...


const nestedArray = [[1, 2, 3], ['one', 'two', 'three']];


function recursiveClone(val) {
return Array.isArray(val) ? Array.from(val, recursiveClone) : val;
}
const nestedArrayCloneUsingFunc = recursiveClone(nestedArray);


const nestedArrayClone = Array.from(nestedArray);


nestedArrayCloneUsingFunc; // [[1, 2, 3], ['one', 'two', 'three']]
nestedArrayClone; // [[1, 2, 3], ['one', 'two', 'three']]


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Comment written by Dmitri Pavlutin on 10/07/2019 11:17:35

Array.from() does only a shallow copy of the array.

Regarding your example: nestedArray[0] === nestedArrayClone[0] equals to true, which means that nestedArrayClone is a shallow copy of nestedArray.

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Comment written by Waheed Afolabi on 10/08/2019 15:54:18

Oh! Now I know and understand the difference...thanks!

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Could you plz explain, the parameters passed in Array.from() in
#5-generate-ranges-of-numbers.

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Thank you!
It was something I was looking for and couldn't find.
I hope to try everything thoroughly soon.

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