如何恢复/重置 window.console.log

Question

I have an application that changes window.console.log to a function.

I want to reset window.console.log back it normal on a certain page, however when I run delete window.console.log; and call console.log('asd'); I get an exception

TypeError: console.log is not a function. (In 'console.log(error)', 'console.log' is undefined)

How do I restore it properly so a certain page can simply console.log normally instead of the custom one I had?

Answer 1

If you're able to access the code from before the application modifies console.log you could do the following:

window.defaultConsoleLog = console.log;

// here would be the code where the application modifies console.log

// calling console.log would now be the modified version from the application:
console.log('Hello');

// calling defaultConsoleLog would now call the original console.log:
defaultConsoleLog.log('Hello');
// OR
window.defaultConsoleLog('Hello');

// you can then reset to the original console.log like this:
console.log = window.defaultConsoleLog;

When you were doing delete window.console.log , this removes the function from the window.console object instead of resetting it.

Answer 2

You can simply store the old native function in an other variable or property and restore it later. For example :

 // Storing the native console.log into a property in window window.oldLog = window.console.log // Overriding the console.log function console.log = (str) => { document.getElementById('logs').textContent += str } console.log('Calling the new console.log') window.oldLog('Calling the old console.log') // Now resetting the native console.log console.log = window.oldLog // Clearing up delete window.oldLog console.log('Calling the restored console.log')

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