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7 Amazing use cases of Array.from() method in JavaScript

Subaash on December 05, 2023

The Array.from() method creates a shallow-copied array instance from an array like object or an iterable. The iterable object could be an array, a...
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Arthur Kh •

Hey! Thank you for article!
Just want to add Object.value already returns Array so you don't have to convert it to Array using Array.from
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It's more used with Maps because Map.prototype.values doesn't return an array, it returns map iterator which could be converted to array using Array.from

const map = new Map([
  [1, 2],
  [2, 4],
  [4, 8],
]);
Array.from(map);
// [[1, 2], [2, 4], [4, 8]]

const mapper = new Map([
  ["1", "a"],
  ["2", "b"],
]);
Array.from(mapper.values());
// ['a', 'b'];

Array.from(mapper.keys());
// ['1', '2'];
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Subaash •

You are absolutely correct. Thank you for your opinion. Future articles will be free of contradictions. Have a nice day 🙂❤️.

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codingjlu •

Nice article. Just wanted to say, the character frequency map isn't very efficient (unnecessary quadratic time complexity) and doesn't end up being in a usable form and has multiple same entries. Something simple using Array#reduce works, e.g.:

const freqMap = str => str.split("").reduce(
  (map, char) => (map[char] ??= 0, map[char]++, map), {}
)
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Subaash •

Thank you for your feedback. I appreciate the suggestion and accept the same. I just wanted to demonstrate some intermediary use cases of Array.from() method. Indeed Array.reduce() is the more efficient approach. I'll consider incorporating that improvement in the future articles. Have a nice day.!

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Mike Stemle •

I wish people would stop writing this exact same article every week.

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Subaash •

I wanted to make the article as unique as possible. But if you find the topic boring, I apologise for the same.