ArrayBuffer and How to use it.
An ArrayBuffer
is an opaque representation of bytes available in memory. It is likened to a Blob
which is an opaque representation of data available on a disk.
Its constructor takes a parameter which is the length in bytes like so:
const myBuffer = new ArrayBuffer(64);
The value of an ArrayBuffer has a read-only property: byteLength
- which expresses its length in bytes.
It provides a slice()
instance method which creates a new ArrayBuffer from an existing one, taking a begin position and an optional length.
const myBuffer = new ArrayBuffer(64);
const slicedBuffer = myBuffer.slice(32, 8);
Fetching Data from the web as an ArrayBuffer
A blob
can be dowloaded from the web and stored into an ArrayBuffer using XHR:
const downloadBlob = (url, cb) => {
const xhr = new XMLHttpRequest();
xhr.open('GET', url);
xhr.responseType = 'arraybuffer';
xhr.onload = () => cb(xhr.response);
xhr.send(null);
}
That's all guys :)
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