JavaScript tips — Find the maximum value in an array of numbers

You can find the largest number in an array in #JavaScript with a single function call and without writing any loops

To find the max value in a very large array, instead use reduce:

This will work even for arrays with millions of elements

[Steve-Richter]

Why does spread fail when the array is large? The max function receives the arguments as an array.

[Chrrs]

i like to explore several approaches for hypothetical situations like this.
Reduce should work pretty fast. i guess it'll hardly take a couple milliseconds.

solution 2: - but probably slow as hell - would be sorting the array and returning the last element of it. Something like:
- 1]

solution 3: coming to my mind is offloading a for ... of ... loop into a function.
let biggest = null;
for (const x of bigArray) {
if (x > biggest) biggest = x;
}

solution 4: the good old for loop with an index.
let biggest = null;
for (let i = 0; i < bigArray.length; i++) {
if (bigArray[i] > biggest) biggest = bigArray[i];
}

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Before posting the comment i took a minute and tested mentioned approaches for performance (out of curiosity)
solution 1: The ReduceFN takes about 15-18ms on my Machine
solution 2: The Sort() approach a whopping 2-3 Seconds (which is expected when sorting a million elements)
solution 3: The for .. of.. loop surprised me. it took 27-30ms - i expected it to be faster than the reduce function as we spare a Math.max function call and have a native loop.
solution 4: the good old for loop with index. 6-9 ms. yep. thats probably offloaded into some C++ magic in the Engine.

But thats a super interesting insight. in some cases you get a x5 performance boost by just switching from a convenient for..of loop to an index based for loop.
i guess reduce also beats the for..of loop because they utilize an index based loop internally?


That was a fun little exercise, thanks for the video :)