Let's break down the provided JSON and explain what is tested, the options compared, pros and cons of each approach, and other considerations.

Benchmark Definition

The benchmark definition represents a JavaScript function that creates a Blob object URL using the createBlobObjectURL function. This function generates a JavaScript code snippet that defines the delayedValue function, which returns a promise that resolves after a specified delay.

"Script Preparation Code": "function delayedValue( milliseconds, value ) {\r\n  return new Promise( ( resolve /*, reject*/ ) => {\r\n    setTimeout( () => resolve( value ), milliseconds );\r\n  } );\r\n}\r\n\r\nfunction createBlobObjectURL( milliseconds, value ) {\r\n  let codes = ``\r\n    + `function delayedValue( milliseconds, value ) {\\n`\r\n    + `  return new Promise( ( resolve /*, reject*/ ) => {\\n`\r\n    + `    setTimeout( () => resolve( value ), milliseconds );\\n`\r\n    + `  } );\\n`\r\n    + `}\\n`\r\n    + `await delayedValue( ${milliseconds}, ${value} );`\r\n    ;\r\n\r\n  let blob = new Blob( [ codes ], { type: \"text/javascript\" } );\r\n  let theBlobObjectURL = URL.createObjectURL( blob );\r\n  return theBlobObjectURL;\r\n}\r\n"

Options Compared

The benchmark definition compares two approaches:

1. Inline JavaScript: The createBlobObjectURL function generates a JavaScript code snippet that is embedded directly into the codes variable.
2. External JavaScript file: The generated JavaScript code is written to a separate file, which is then referenced by the blob object.

Pros and Cons

• Inline JavaScript:
  • Pros: Reduced memory usage, as no additional file is created.
  • Cons: Increased complexity, as the generated JavaScript code needs to be parsed and executed.
• External JavaScript file:
  • Pros: Easier maintenance, as changes can be made to the external file without affecting the createBlobObjectURL function.
  • Cons: Increased memory usage, as an additional file is created.

Other Considerations

• The benchmark definition uses promises to simulate asynchronous behavior. This makes it easier to test performance under different conditions.
• The createBlobObjectURL function uses the URL.createObjectURL() method to create a blob object URL. This allows the generated JavaScript code to be executed in a sandboxed environment.

Library: URL

The URL library is used to create a blob object URL. The URL.createObjectURL() method takes an array of byte-like values (in this case, a string containing JavaScript code) as input and returns a URL that can be used to access the blob.

Special JS Feature/Syntax

• Template literals: The createBlobObjectURL function uses template literals to generate the JavaScript code snippet. This feature is available in modern JavaScript engines.
• Await syntax: The benchmark definition uses the await keyword to simulate asynchronous behavior. This feature is also available in modern JavaScript engines.

Alternatives

Other alternatives for creating blob object URLs include:

• Using a separate library, such as jszip
• Creating a custom function to generate the URL
• Using a different approach, such as using the fetch() API with a blob as the response