Magnetiq

I had been working on parsing the source of JavaScript function instances when I realized that Function.prototype.toString() may return parts of the original comments in the source code, depending on the browser. I’ve done a quick test to capture the different behaviours of popular browsers.

Here’s my test script:

function/*post-keyword*/fn/*post-name*/()/*post-parens*/{
    /*inside*/
}

document.write(fn.toString());

And here are the results I got on different browsers:

And out of the browser context:

While looking for the best solution to extract the parts that I need, I’ve implemented a workaround. Sort of. If blocking the problem can be considered a workaround:

var functionToStringHasComments = /PROBE/.test(function () {/*PROBE*/});

// ...

if (functionToStringHasComments) {
    throw "...";
}