javascript - Can't access object property, even though it shows up in a console log

Below, you can see the output from these two logs. The first clearly shows the full object with the property I'm trying to access, but on the very next line of code, I can't access it with config.col_id_3 (see the "undefined" in the screenshot?). Can anyone explain this? I can get access to every other property except field_id_4 as well.

console.log(config);
console.log(config.col_id_3);

This is what these lines print in Console

Answer

The output of console.log(anObject) is misleading; the state of the object displayed is only resolved when you expand the > in the console. It is not the state of the object when you console.log'd the object.

Instead, try console.log(Object.keys(config)), or even console.log(JSON.stringify(config)) and you will see the keys, or the state of the object at the time you called console.log.

You will (usually) find the keys are being added after your console.log call.