I want to modify console.log so that it saves everything that the application outputs to the mand line using console.log.

I have tried

var log = console.log;

console.log = function () {
    // fs.appendFile('log.txt ..
    log.apply(log, arguments);
}

But it gives me the error

 Illegal invocation

I want to modify console.log so that it saves everything that the application outputs to the mand line using console.log.

I have tried

var log = console.log;

console.log = function () {
    // fs.appendFile('log.txt ..
    log.apply(log, arguments);
}

But it gives me the error

 Illegal invocation

• javascript
• node.js

Share Improve this question Follow asked Jun 11, 2015 at 18:44 afonso-botafonso-bot 3511 silver badge44 bronze badges

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1 Answer 1

Sorted by: Reset to default 10

The first arguments to apply is what this will refer to. To mimic a call to console.log(), you have to pass console, not the function itself:

 var log = console.log;

 log.apply(console, arguments);
 // log.apply(this, arguments); would work as well