Create an ArrayBuffer from an array (integers) and vice versa

Question

It seems so simple, but I can't figure out how to convert Array with integers to ArrayBuffer and return to Array . There are many examples in which strings are converted to an ArrayBuffer , for example here .
Using these examples, I created this:

 /** * Convert string to array buffer. * * @param {Array.<int>} array * @returns {ArrayBuffer} */ self.arrayToArrayBuffer = function( array ) { var length = array.length; var buffer = new ArrayBuffer( length * 2 ); var view = new Uint16Array(buffer); for ( var i = 0; i < length; i++) { view[i] = array[i]; } return buffer; } 

Then the array also needs to be converted back. For this, I use:

 var array = new Uint16Array(arrayBuffer); 

This solution seems to work, but is there an easier way to do this?

UPDATE

It should also work for an array like:

 var array = [3,7426,78921] 

Answer 1

Yes, there is a simple way without manually recording the loop (the loop still exists somewhere in the background):

 new Uint16Array([1,2,3]); 

It's all. Of course, floating numbers will be rounded and large numbers will overflow.

Convert a typed array to a buffer

The buffer of any typed array is accessible through the .buffer property, since anyone can read MDN :

 new Uint16Array([1,2,3]).buffer; 

Choosing the Right Typed Array

We will warn that the mentioned Uint16Array will contain integers (without floating point) between zero and 65535. To save any javascript number ^1, you will want to use Float64Array - the largest, only 8 bytes.

_{1:. This is an unlimited double, which appears to be 64 bit IEEE 754 number}

A map has been created here that displays important information related to the types of numerical data:

 var NUMBER_TYPE = [ {name: "uint8", bytes:1, max: 255, min: 0, floating: false, array: Uint8Array}, {name: "int8", bytes:1, max: 127, min: -128, floating: false, array: Int8Array}, {name: "uint16", bytes:2, max: 65535, min: 0, floating: false, array: Uint16Array}, {name: "int16", bytes:2, max: 32767, min: -32768, floating: false, array: Int16Array}, {name: "uint32", bytes:4, max: 4294967295, min: 0, floating: false, array: Uint32Array}, {name: "int32", bytes:4, max: 2147483647, min: -2147483648, floating: false, array: Int32Array}, {name: "float64", bytes:8, max: Number.MAX_VALUE, min: Number.MIN_VALUE, floating: true , array: Float64Array} ]; 

The float 32 is missing, because I could not calculate the necessary information for it. The map, as it is, can be used to compute the smallest typed array you can put in a number:

 function findNumberType(num) { // detect whether number has something after the floating point var float = num!==(num|0); // Prepare the return variable var type = null; for(var i=0,l=NUMBER_TYPE.length; i<l; i++) { // Assume this type by default - unless break is hit, every type ends as `float64` type = NUMBER_TYPE[i]; // Comparison asserts that number is in bounds and disalows floats to be stored // as integers if( (!float || type.floating) && num<=type.max && num>=type.min) { // If this breaks, the smallest data type has been chosen break; } } return type; } 

Used as:

 var n = 1222; var buffer = new (findNumberType(n).array)([n]); 

Please note that this only works if NUMBER_TYPE properly ordered.

Answer 2

You cannot use ArrayBuffer directly, but you can create a typed array from a regular array using the method from :

 let typedArray = Int32Array.from([-2, -1, 0, 1, 2])