JavaScript is Crazy - Part 2

Hello Folks 👋

What’s up friends, this is SnowBit here. I am a young passionate and self-taught developer and have an intention to become a successful developer.

Today, I am here again with a crazy thing in JavaScript.

So, let’s get started.

console.log(Math.max())

As we all know the biggest positive number is ∞ (infinity). So the out of the above code snippet should be positive Infinity. For better understanding, you can see the attached graph

console.log(Math.max())
// -Infinity

But, as we know JavaScript is crazy 🤪; The output of this code is -Infinity. Don't believe it? check out the demo - https://jsfiddle.net/ce0hkoLs/

Now, here come Math.min() it is converse of Math.max

As we all know that lowest negative number is -∞(-infinity), but we know that’s not the case.

console.log(Math.min())
// Infinity

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We all know simple math, right? Now again we have a crazy thing with mathematics in JavaScript.

console.log(0.5 + 0.1 == 0.6)
// true

Yes, 0.5 + 0.1 == 0.6 is true, isn’t it?

Now here comes some thing crazy,

console.log(0.1 + 0.2 == 0.3)

As we know, 0.1 + 0.2 == 0.3 is true, but JavaScript don’t think that. Somehow, JavaScript thinks it is false, I actually don’t know the exact reason for that let me know in the comments if you know it.

There, the output will be,

console.log(0.1 + 0.2 == 0.3)
// false

Try it - https://jsfiddle.net/feahj1s2/

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Comments

[Lou Cyx]

Math.max gives you the maximum number of a given list of numbers, if you only provide one number, then that number is "the max", but it needs to be greater than something, so its compared to the smallest possible number, which in JS is -Infinity. So if you don't provide any number, the max value is -Infinity. The idea also is that if you put the output of a Math.max call into another call to the same function, the comparison will be made against that -Infinity. Same applies to Math.min but with Infinity. Hope this makes it more clear for you

Cheers!

[Dhairya Shah]

Great explaination!

[𒎏Wii 🏳️‍⚧️]

It actually makes a lot of sense that the maximum of nothing is the lowest possible number.

Consider this example:

let a = [/* some numbers */]
let b = [/* some numbers */]
Math.max(Math.max(...a), Math.max(...b))
// Should be the same as
Math.max(...a, ...b)

Consider now that a = [] and b = [2]

If Math.max(...[]), which is the same as Math.max() returned positive infinity, then the first example would be Math.max(Math.max(), Math.max(2)) which would return positive infinity, even though the second example would return 2 because Math.max(...[], ...[2]) is the same as just Math.max(2).

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The second one is really just the age-old topic of floating point inaccuracy. It's interesting to explore why it happens with one set of numbers but not with another, but on its own, it's really just a well-known phenomenon.

[Jon Randy 🎖️]

As for the second point, it is not really a JavaScript issue - rather it is an issue with the way floating point (decimal) numbers are stored internally. This website gives a fairly succinct explanation and examples of the issue in various languages.

[Dhairya Shah]

haha, website is amazing specially url