Does javascript support binary data?
In web-development we meet binary data mostly while dealing with files (create, upload, download). Another typical use case is image processing. Show That’s all possible in JavaScript, and binary operations are high-performant. Although, there’s a bit of confusion, because there are many classes. To name a few:
Binary data in JavaScript is implemented in a non-standard way, compared to other languages. But when we sort things out, everything becomes fairly simple. The basic binary object is We create it like this:
This allocates a contiguous memory area of 16 bytes and pre-fills it with zeroes.
Let’s eliminate a possible source of
confusion.
To manipulate an A view object does not store
anything on its own. It’s the “eyeglasses” that give an interpretation of the bytes stored in the For instance:
So, the binary data in an
But if we’re going to write into it, or iterate over it, basically for almost any operation – we must use a view, e.g:
TypedArrayThe common term for all these views ( Please note, there’s no constructor called When you see something like Typed arrays behave like regular arrays: have indexes and are iterable. A typed array constructor (be it There are 5 variants of arguments:
We can create a To access the underlying
So, we can always move from one view to another:
Here’s the list of typed arrays:
No Please note, despite of the names like That’s logical, as Out-of-bounds behaviorWhat if we attempt to write an out-of-bounds value into a typed array? There will be no error. But extra bits are cut-off. For instance, let’s try to put 256 into For bigger numbers, only the rightmost (less significant) 8 bits are stored, and the rest is cut off: So we’ll get zero. For 257, the binary form is In other words, the number modulo 28 is saved. Here’s the demo:
TypedArray methods
We can iterate, There are few things we can’t do though:
There are two additional methods:
These methods allow us to copy typed arrays, mix them, create new arrays from existing ones, and so on. DataViewDataView is a special super-flexible “untyped” view over
The syntax:
For instance, here we extract numbers in different formats from the same buffer:
Summary
To do almost any operation on
In most cases we create and operate directly on typed arrays, leaving There are also two additional terms, that are used in descriptions of methods that operate on binary data:
We’ll see these terms in the next chapters. Here’s a cheatsheet: How does JavaScript handle binary data?JavaScript can handle binary data via typed arrays. And here is a library for dealing with binary files, that you can use as a reference point for your application.
Can we send binary data in JSON?The JSON format natively doesn't support binary data. The binary data has to be escaped so that it can be placed into a string element (i.e. zero or more Unicode chars in double quotes using backslash escapes) in JSON.
What is binary data in node JS?Binary is simply a set or a collection of 1 and 0 . Each number in a binary, each 1 and 0 in a set are called a bit. Computer converts the data to this binary format to store and perform operations. For example, the following are five different binaries: 10, 01, 001, 1110, 00101011.
How do you send binary data?Here are a few ways to do this:. JSON / XML. Probably the easiest and most compatible way to send the data is to serialize it to JSON or XML. ... . BSON. However if the extra message size is not something you can put up with, then you can use a form of binary serialization. ... . multipart/form-data.. |