Override post requests-CodePudding

I have this code that I put in my console:

XMLHttpRequest.prototype.send = function(body) {
    // modifies inputted request
    newBody = JSON.parse(body);
    newBody.points = 417;

  // sends modified request
    this.realSend(JSON.stringify(newBody));
}

It is supposed to make the points 417 every time it sends a request, but when I look at the request body, it still says the original amount of points. Any help?

CodePudding user response：

Try to add an alert() or console.log() into your modified XMLHttpRequest.prototype.send to check if it actually works. There is a way to prevent this kind of modifications silently.

CodePudding user response：

As others have noted, the error you are experiencing is hard to diagnose exactly without seeing how you created this.realSend.

However, this code will work:

const send = XMLHttpRequest.prototype.send;
XMLHttpRequest.prototype.send = function (body) {
    const newBody = JSON.parse(body);
    newBody.points = 417;
    send.call(this, JSON.stringify(newBody));
};

Note that instead of storing the original send method on XMLHttpRequest.prototype, I've kept in a separate variable and simply invoked it with the correct this value through send.call(). This seems like a cleaner implementation with less chance for conflicts with other code.

See this codesandbox for a working example.