Everything you could possibly need to know about numbers in JavaScript ↓

JavaScript represents numbers as double-precision 64-bit binary format IEEE 754 values, similar to Java's and C's double type.

This means that it can represent fractions, but only up to around 17 digits. It's also subject to rounding errors (0.1 + 0.2 != 0.3). 

The biggest possible JavaScript number is around 1.8e308. All higher values are converted to the constant Infinity.

However, we should not use numbers higher than Number.MAX_SAFE_INTEGER (9007199254740991), as the numbers above it may not be correct. 

JavaScript has no concept of integers; Integers are also represented as doubles.

Another important related value is NaN, or Not A Number. It is returned when you do bad math (like "a" - 1 or parseInt("a"))

Here are a few handy Number related functions:

- parseInt: parses a string to an integer
- parseInt: parses a string to a float
- Number: parses a string to a number or float. The benefit of using this is that it correctly parses scientific notation, octal, hex, Infinity, etc

- isNaN: used to check if something is not a number

You can use numbers in many ways:

- as plain numbers: 123, 123.21
   - be careful with leading zeros. 0888 is parsed as decimal, but 0777 is parsed as octal
- In exponential form: 1e7, 2e-9
- Binary: 0b111010
- Octal: 0o123
- Hex: 0xdeadbeef
- With _s: 100_000 = 100000 (sugar)

To overcome the limitation on the size of numbers, JavaScript has a new syntax for numbers called BigInt. You can use BigInt by adding an "n" to the end of numbers. 123n is a BigInt

There is supposed to be no limit to BigInt, but in my testing, it errored at 1n<<(1n<<30n)

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You can read the unrolled version of this thread here: https://typefully.com/SiddharthShyn/50aKIo9

Numbers in JavaScript

Here are the JavaScript concepts you need to learn to make the leap to the advanced javascript developer.

A thread 🧵 👇 

(1/n) Get familiar with the standard library.

I can't stress this enough.
The standard library will be your very best friend in every JavaScript app.

Methods you should get familiar with:

Array: push, pop, shift, unshift, map, reduce, filter, every, some, forEach, find, findIndex, join, slice, 
Object: keys, values, entries, fromEntries, assign
Date: set*, toLocaleDateString
Function: call, apply, bind

String: padEnd, padStart, includes, indexOf, repeat, replace, search, slice, trim

Also look at Map, Set, Proxies, and Symbol. They aren't very commonly used but are really helpful when you need them.

I've used every single one of these at least 5 times. You will too.

MDN is your best friend here. You can go to mdn.io/something to instantly go to the documentation for it. 

(2/n) Go bleeding edge

New proposals are being made all the time. I occasionally take a look at https://github.com/tc39/proposals to see what's up and coming.

With transpilers, you can use these features in your code right now, without waiting

If you don't wanna wade through all that, you can check out the quick list I made of the most interesting proposals here: https://dev.to/siddharthshyniben/10-interesting-ecmascript-proposals-4k3n

Some of them are:

- Optional chaining: a?.b?.c
- Nullish coalescing: ??
- Exponent operator: **
- Logical assignment: ??=, &&=, ||=, 
- (personal fav) Piping: f(g(x)) becomes x |> g |> f

(3/n) Learn more about the concepts

Recursion, async-await, inheritance, prototypes, modules, closures.
These are some important concepts to know about.

The sidebar at https://developer.mozilla.org/en-US/docs/Web/JavaScript has some good tutorials on these.


(4/n) Miscellaneous

There are too many things to fit this thread, so let's do a quickfire round.

- Generator Functions
- Intl. This is super handy while working with Dates
- SameValue https://developer.mozilla.org/en-US/docs/Web/JavaScript/Equality_comparisons_and_sameness

(5/n) Practice

You can't get good without practice. Get on competitive coding sites like @CodinGame and code.golf to push yourself to use optimal language tricks.

In my opinion, these are better than most real-life projects as you can focus on the JavaScript

Welp, that was a huge totally unorganized thread

If you somehow liked it, please do retweet the first tweet! It keeps me motivated :)

You can read the unrolled version of this thread here: https://typefully.com/SiddharthShyn/znxjXpn

Make the leap to the advanced javascript developer.

It's not that difficult to learn how to code.

It's all about the repetition. Keep coding, and you'll be a master in no time.

The hardest things in coding: deciding what to code, then naming 😆 

JavaScript has tons of methods to manipulate arrays.

Here's a list of the top methods which will come in handy 🧵 👇 

(0/6) `.map()`

map is the essential Array method. It changes every item in an array into another value.

(1/6) `.filter()`

Another essential function used to filter out values from an array

(2/6) `.includes()`

This method is used to check if an array includes a value.

(3/6) `.every()`

This method is used to check if every item in an array matches a condition

(4/6) `.reduce()`

This is an advanced method used to transform a list of values into a single value. It's rarely used, but when you use it it's extremely powerful.

(5/6) `.find()`

As its name suggests, it's used to find a matching item from an array. This is basically `.filter()` but it returns just the first item which matches.

(6/6) `.some()`

Similar to `.every()`, it returns true if at least one of the items in the array matches a condition.

Hey, I'm Siddharth. I've been coding for around 5 years and I also blog often. 

I'm planning on ramping up my content game, so if you want more like this, be sure to follow! 

You can read the unrolled version of this thread here: https://typefully.com/SiddharthShyn/8U5NaJnplo6J