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JavaScript DataView getInt8() Method

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The JavaScript DataView getInt8() method reads 1-byte data at the specified byte offset of this DataView and decodes it as an 8-bit signed integer. If you do not specify the byteOffset parameter value to this method, it always returns 0.

This method throws a 'RangeError' exception if the value of the byteOffset parameter is outside the bounds of the data view.

Syntax

Following is the syntax of the JavaScript DataView getInt8() method −

getInt8(byteOffset)

Parameters

This method accepts a parameter named 'byteOffset', which is described below −

  • byteOffset − The position in the DataView from which to read the data.

Return value

This method returns a signed integer between the range of -128 to 127, inclusive.

Example 1

The following example demonstrates the usage of the JavaScript DataView getInt8() method.

<html>
<body>
<script>
   const buffer = new ArrayBuffer(16);
   const data_view = new DataView(buffer);
   const value = 127;
   const byteOffset = 0;
   document.write("Value: ", value);
   document.write("<br>The byte offset: ", byteOffset);
   //storing the data
   data_view.setInt8(byteOffset, value);
   //using the getInt8() method
   document.write("<br>The stored value: ", data_view.getInt8(byteOffset));
</script>
</body>
</html>

Output

The above program returns the store data value as −

Value: 127
The byte offset: 0
The stored value: 127

Example 2

If we do not pass the byteOffset parameter to this method, it will return 0.

The following is another example of the JavaScript DataView getInt8() method. We use this method to read 1 byte data value 40 at the specified byteOffset 1. Since we do not pass the byteOffset parameter to this method, it will return 0.

<html>
<body>
<script>
   const buffer = new ArrayBuffer(8);
   const data_view = new DataView(buffer);
   const value = 40;
   const byteOffset = 1;
   document.write("Value: ", value);
   document.write("<br>The byte offset: ", byteOffset);
   //storing the data
   data_view.setInt8(byteOffset, value);
   //using the getInt8() method
   document.write("<br>The data_view.getInt8() returns: ", data_view.getInt8());
</script>
</body>
</html>

Output

After executing the above program, it will return 0.

Value: 40
The byte offset: 1
The data_view.getInt8() returns: 0

Example 3

If the byteOffset parameter is outside the bounds of this data view, it will throw a 'RangeError' exception.

<html>
<body>
<script>
   const buffer = new ArrayBuffer(8);
   const data_view = new DataView(buffer);
   const value = 121;
   const byteOffset = 2;
   document.write("Value: ", value);
   document.write("<br>The byte offset: ", byteOffset);
   //storing the data
   data_view.setInt8(byteOffset, value);
   try {
      //using the getInt8() method
      document.write("<br>The data_view.getInt8() returns: ", data_view.getInt8(-1));
   } catch (error) {
      document.write("<br>", error);
   }
</script>
</body>
</html>

Output

Once the above program is executed, it will throw a 'RangeError' exception as −

Value: 121
The byte offset: 2
RangeError: Offset is outside the bounds of the DataView
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