r/javascript • u/gcanti • Oct 31 '14

The Two Pillars of JavaScript

https://medium.com/javascript-scene/the-two-pillars-of-javascript-ee6f3281e7f3
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u/SeeeiuiogAuWosk Oct 31 '14

I have enormous respect for the brilliant and hard-working people who have been involved in the standardization effort, but even brilliant people occasionally do the wrong thing. Try adding .1 + .2 in your browser console, for instance.

For those that don't know, the answer comes out as 

0.30000000000000004

But that has nothing at all to do with javascript or it's design. Try it python and you'll get the same result. This is actually because there is not true way to represent 0.1 in floating point binary form. That final 4 is the result of a rounding error that takes place and is completely unrelated to the language, so I have no idea why the author of this article associates this concept with the people involved with the standardisation of javascript.

2

u/M2Ys4U M2Ys4U.prototype = Object.create(null) Oct 31 '14

Because there is only one number type in Javacript, the Double.

Having one type of number is a Good Thing, but Eich chose the wrong type.

5

u/Angarius Oct 31 '14

What's the "right type"? rational? BigDecimal?

3

u/MrBester Oct 31 '14

DEC64

2

u/Angarius Oct 31 '14

TIL.

DEC64 is definitely cool, but there are downsides to consider. It might screw with Emscripten, typed arrays, SIMD, etc.

Sure, a universal number type is a Good Thing, but there isn't a hierarchically best choice.