How to check if a variable is a typed array in javascript?

ArrayBuffer.isView should help you out.

var data = [0,1,2]
var dataBuffer = new ArrayBuffer( data )
var dataBufferView = new Float32Array( data )

ArrayBuffer.isView(data) //false
ArrayBuffer.isView(dataBuffer) //false
ArrayBuffer.isView(dataBufferView) //true
dataBuffer instanceof ArrayBuffer //true