Experimental: This is an experimental technology
Check the Browser compatibility table carefully before using this in production.

The maxByteLength accessor property of SharedArrayBuffer instances represents the maximum length, in bytes, that the SharedArrayBuffer can be grown to.


The maxByteLength property is an accessor property whose set accessor function is undefined, meaning that you can only read this property. The value is established when the shared array is constructed, set via the maxByteLength option of the SharedArrayBuffer() constructor, and cannot be changed.

If this SharedArrayBuffer was constructed without specifying a maxByteLength value, this property returns a value equal to the value of the SharedArrayBuffer's byteLength.


Using maxByteLength

In this example, we create a 8-byte buffer that is resizable to a max length of 16 bytes, then return its maxByteLength:

const buffer = new SharedArrayBuffer(8, { maxByteLength: 16 });

buffer.maxByteLength; // 16


Resizable ArrayBuffer and growable SharedArrayBuffer
# sec-get-sharedarraybuffer.prototype.maxbytelength

Browser compatibility

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See also