Uncaught TypeError: Illegal invocation in JavaScript

Question

I'm creating a lambda function that executes a second function with a concrete params. This code works in Firefox but not in Chrome, its inspector shows a weird error, Uncaught TypeError: Illegal invocation. What's wrong with my code?

var make = function(callback,params){
    callback(params);
}

make(console.log,'it will be accepted!');

Namangan

if i replace console.log with console.log.bind(console), it works in Chrome 12. – Perplexed

@DanD—that indicates that log expects to be called as a method of console, i.e. that its this keyword must reference the console object. – Palpable

your make function is equivalent to callback.call(null,params) – Jerrybuilt

I would like to note that in old versions of IE console.log can be a callable host-object (without call, apply or bind methods) instead of being a function. – Radiocommunication

https://mcmap.net/q/159503/-jquery-illegal-invocation – Shorthand

Answer 1

The console's log function expects this to refer to the console (internally). Consider this code which replicates your problem:

var x = {};
x.func = function(){
    if(this !== x){
        throw new TypeError('Illegal invocation');
    }
    console.log('Hi!');
};
// Works!
x.func();

var y = x.func;

// Throws error
y();

Here is a (silly) example that will work, since it binds this to console in your make function:

var make = function(callback,params){
    callback.call(console, params);
}

make(console.log,'it will be accepted!');

This will also work

var make = function(callback,params){
    callback(params);
}

make(console.log.bind(console),'it will be accepted!');

Everlasting

Answer 2

You can wrap the function which need 'this' to a new lambda function, and then use it for your callback function.

function make(callback, params) {
  callback(params);
}

make(function(str){ console.log(str); }, 'it will be accepted!');

Enzymology