Float64Array

//  
const float64 = new Float64Array(2);
float64[0] = 42;
console.log(float64[0]); // 42
console.log(float64.length); // 2
console.log(float64.BYTES_PER_ELEMENT); // 8

//  
const x = new Float64Array([21, 31]);
console.log(x[1]); // 31

//  TypedArray 
const y = new Float64Array(x);
console.log(y[0]); // 21

// ArrayBuffer 
const buffer = new ArrayBuffer(64);
const z = new Float64Array(buffer, 8, 4);
console.log(z.byteOffset); // 8

//  
const iterable = (function* () {
  yield* [1, 2, 3];
})();
const float64FromIterable = new Float64Array(iterable);
console.log(float64FromIterable);
// Float64Array [1, 2, 3]