1. Open your command-line application, and navigate to your workspace.
2. Create a new folder named 05-05-creating-shared-array-buffer.
3. Copy or create an index.html that loads and runs a main function from main.js.

4. Create a main.js file with a main method that defines constants for NUM_COUNT, BYTES_FOR_32_BIT, ARRAY_SIZE, and MAX_NUMBER:

export function main() { 
  const NUM_COUNT = 2048; 
  const BYTES_FOR_32_BIT = 4; 
  const ARRAY_SIZE = NUM_COUNT * BYTES_FOR_32_BIT; 
  const MAX_NUMBER = 1024; 
} 

5. Next, create a SharedArrayBuffer that is of size ARRAY_SIZE, and create an Int32Array casting of it:

export function main() { 
  // ... 
  const sab = new SharedArrayBuffer(ARRAY_SIZE);
  const intBuffer = new Int32Array(sab);
}  

6. Fill the intBuffer with random numbers between 0 and MAX_NUMBER:

export function main() { 
  // ... 
  // fill with random numbers  // fill with random numbers
  intBuffer.forEach((value, index) => {
    intBuffer[index] = Math.random() * MAX_NUMBER;
  });
} 

7. Calculate and print the sum of the values in the array:

 export function main() { 
  // ... 
  // sum the ints
  const sum = intBuffer.reduce((acc, number) =>
    acc + number
  , 0);
} 

8. Start your Python web server and open the following link in your browser:
   http://localhost:8000/.

9. You should see the following output: