Collections - Scripting in Java: Integrating with Groovy and JavaScript - page 239

Typed Arrays
Typed array views are array-like objects that deal with a specific type of values such as
32-bit signed integers. They provides a means to read and write the specific type of data
to the ArrayBuffer . In a typed array view, all data values are of the same size. Table 7-1
contains the list of typed array views, their sizes and descriptions. The size in the table
is the size of one element of the typed array view. For example, Int8Array contains
elements that are 1 byte in length each. You can think of the Int8Array as a byte array
type in Java, the Int16Array as the short array type in Java, and Int32Array as the int
array type in Java.

Table 7-1. The List of Typed Array Views, Their Sizes, and Descriptions

Typed Array View Size in Byte Description

Int8Array 1 8-bit 2's complement signed integer

Uint8Array 1 8-bit unsigned integer

Uint8ClampedArray

1 8-bit unsigned integer (clamped)

Int16Array 2 16-bit 2's complement signed integer

Uint16Array 2 16-bit unsigned integer

Int32Array 4 32-bit 2's complement signed integer

Uint32Array 4 32-bit unsigned integer

Float32Array

4 32-bit IEEE floating point

Float64Array 8 64-bit IEEE floating point

■ a typed array is a fixed-length, dense array-like object, whereas an Array object is
a variable-length array that may be sparse or dense.

Tip

Let us differentiate between two array types: Uint8Array and Uint8ClampedArray .
Elements in both arrays contain 8-bit unsigned integers ranging from 0 to 255.
Uint8Array uses modulo 256 to store values in the array whereas Uint8ClampedArray
clamps the values between 0 and 255 (inclusive). For example, if you store 260
in a UInt8array , 4 is stored because 260 modulo 256 is 4. If you store 260 in a
Uint8ClampedArray , 255 is stored because 260 is greater than 255 and the upper
limit is clamped at 255. Similarly, storing -2 stores 254 in a Uint8Array and 0 in a
Uint8ClampedArray .
Each of the typed array view object defined the following two properties:
• BYTES_PER_ELEMENT
• name