I create an array of 3 bytes : array_A

I modify it : array_A[0]=34

I create a 8-byte buffer with a Uint8array view referring to array_A:

let typedarray = new Uint8Array(a);

why such a result with console.log ?

{  
  "0": 0, // where is 34 ?  
  "1": 0,  
  "2": 0  
}

let array_A=new ArrayBuffer(3);
array_A[0]=34;
console.log(array_A);
let typedarray = new Uint8Array(array_A);
console.log(typedarray);