javascript - Puppeteer console.log - How to look inside JSHandle@object?

Question

I have a React/Redux app that I am testing using Puppeteer. Based on the documentation, I am using the following code to show the console outputs:

page.on('console', msg => {
    for(let i = 0; i < msg.args().length; ++i) {
        let text = msg.args()[i];
        console.log(`${i}: ${text}`);
    }
});

However, when the redux-logger logs an object to console (prevState, nextState), Puppeeter shows JSHandle@object in my console outputs instead. How do I see the keys and properties inside this object?

Answer 1

If you place the consoleMessage.args() directly inside console.log() without enclosing them in template literals, you can print the keys and values of the JSHandles that represent each argument passed to console.log() in the page context:

page.on('console', msg => {
  for (let i = 0; i < msg.args().length; i++) {
    console.log(msg.args()[i]);
  }
});

The beginning of the result will look something like this:

JSHandle {
  _context:
   ExecutionContext {
     _client:
      CDPSession {
        domain: null,
        _events: [Object],
        ...