从返回的函数中调用function.apply不会传递参数

Question

I need to call a varying number of functions with an arbitrary list of arguments.

The general use case is to assign formatting functions to different cells in a generated table. I need to be able to call multiple formatters but I can only assign one formatting function, hence the multi().

The function returned from multi will be applied as the actual formatter with a set of arguments that need to be passed to each one of the individual formatters.

    function multi(){
        var fns = arguments;
        return function(){
            var params = arguments;

            console.log(params);

            _.each(fns, function(fn){
                    fn.apply(params);
            }, this);
        };
    };

Problem: arguments in 'params' are available inside multi() but are not actually passed to the applied functions. The parameters are available to the console.log() call but are undefined the actual functions.

You can check this bin for an example of this issue: http://jsbin.com/pekomopi/1/edit

Thanks!

Answer 1

The apply function takes in two arguments. The first argument is the this of the function. The second argument is the array of arguments.

All you have to do is change the line to fn.apply(this, params) . With this being whatever object you want to be the this of fn .