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Sep 8, 2012 · I wanted a more exact and useful answer to this question. Here's the real answer (adjust accordingly if you want a byte array specifically; obviously the math will be off by a factor of 8 bits : 1 byte):
Jun 14, 2012 · Creating one of these arrays is fairly trivial. // creating an array of bytes, with 1024 elements. var bytes = new Uint8Array(1024); There are other typed arrays available, handling 16 bit and 32 bit integers. // creating an array of 16 bit integers, with 128 elements. var array_16bit = new Uint16Array(128);
Call the encode () method on the object to convert the string to a byte array. This approach works in the browser and Node.js. The TextEncoder () constructor creates a TextEncoder object that is used to generate a byte stream with UTF-8 encoding. The last step is to use the TextEncoder.encode () method. The method takes a string as a parameter ...
- Overview
- Description
- Constructor
- Static properties
- Static methods
- Instance properties
- Instance methods
- Examples
The ArrayBuffer object is used to represent a generic raw binary data buffer.
It is an array of bytes, often referred to in other languages as a "byte array". You cannot directly manipulate the contents of an ArrayBuffer; instead, you create one of the typed array objects or a DataView object which represents the buffer in a specific format, and use that to read and write the contents of the buffer.
The ArrayBuffer() constructor creates a new ArrayBuffer of the given length in bytes. You can also get an array buffer from existing data, for example, from a Base64 string or from a local file.
ArrayBuffer is a transferable object.
Resizing ArrayBuffers
ArrayBuffer objects can be made resizable by including the maxByteLength option when calling the ArrayBuffer() constructor. You can query whether an ArrayBuffer is resizable and what its maximum size is by accessing its resizable and maxByteLength properties, respectively. You can assign a new size to a resizable ArrayBuffer with a resize() call. New bytes are initialized to 0. These features make resizing ArrayBuffers more efficient — otherwise, you have to make a copy of the buffer with a new size. It also gives JavaScript parity with WebAssembly in this regard (Wasm linear memory can be resized with WebAssembly.Memory.prototype.grow()).
Transferring ArrayBuffers
ArrayBuffer objects can be transferred between different execution contexts, like Web Workers or Service Workers, using the structured clone algorithm. This is done by passing the ArrayBuffer as a transferable object in a call to Worker.postMessage() or ServiceWorker.postMessage(). In pure JavaScript, you can also transfer the ownership of memory from one ArrayBuffer to another using its transfer() or transferToFixedLength() method. When an ArrayBuffer is transferred, its original copy becomes detached — this means it is no longer usable. At any moment, there will only be one copy of the ArrayBuffer that actually has access to the underlying memory. Detached buffers have the following behaviors: •byteLength becomes 0 (in both the buffer and the associated typed array views). •Methods, such as resize() and slice(), throw a TypeError when invoked. The associated typed array views' methods also throw a TypeError.
ArrayBuffer[@@species]
The constructor function that is used to create derived objects.
ArrayBuffer.isView()
Returns true if arg is one of the ArrayBuffer views, such as typed array objects or a DataView. Returns false otherwise.
These properties are defined on ArrayBuffer.prototype and shared by all ArrayBuffer instances.
ArrayBuffer.prototype.byteLength
The size, in bytes, of the ArrayBuffer. This is established when the array is constructed and can only be changed using the ArrayBuffer.prototype.resize() method if the ArrayBuffer is resizable.
ArrayBuffer.prototype.constructor
The constructor function that created the instance object. For ArrayBuffer instances, the initial value is the ArrayBuffer constructor.
ArrayBuffer.prototype.detached
ArrayBuffer.prototype.resize()
Resizes the ArrayBuffer to the specified size, in bytes.
ArrayBuffer.prototype.slice()
Returns a new ArrayBuffer whose contents are a copy of this ArrayBuffer's bytes from begin (inclusive) up to end (exclusive). If either begin or end is negative, it refers to an index from the end of the array, as opposed to from the beginning.
ArrayBuffer.prototype.transfer()
Creates a new ArrayBuffer with the same byte content as this buffer, then detaches this buffer.
Creating an ArrayBuffer
In this example, we create a 8-byte buffer with a Int32Array view referring to the buffer:
Feb 2, 2024 · It needs a separate view object to read/write. Syntax: new ArrayBuffer (length_in_bytes); The above code will call the ArrayBuffer constructor to create a new ArrayBuffer instance with the specified byte length. Let’s create an ArrayBuuffer with a length of 8 bytes. let myTypedArrayBuffer =new ArrayBuffer (8);
Jul 11, 2022 · 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: ArrayBuffer, Uint8Array, DataView, Blob, File, etc. Binary data in JavaScript is implemented in a non-standard way, compared to other languages.
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Oct 6, 2023 · There are several methods to encode a string into a byte array in JavaScript, depending on the encoding scheme and the environment. Here are some of the most common functions: 1. Using TextEncoder object. This method can be used to create a TextEncoder object that can encode strings into byte arrays using UTF-8 encoding, which is the most ...
