在循环内向现有功能添加代码

Question

In an object I have defined some events: the key is the event name and the value is the callback function. Here is an exemple:

vm.events = {
    check_node: function(node, selected){
        ...
    },
    uncheck_node: function(node, selected){
        ...
    }
};

I want to add some code to those functions so I did the following:

for (var evt in scope.tree.events) {
    if (scope.tree.events.hasOwnProperty(evt)) {
        var cb = scope.tree.events[evt];
        scope.tree.events[evt] = function(...args){
            cb(...args);
            controller.$setDirty();
            scope.$evalAsync();
        };
        scope.tree.view.on(evt.indexOf('.') > 0 ? evt : evt + '.jstree',  scope.tree.events[evt]);
    }

But JSHint logs the following warning:

Functions declared within loops referencing an outer scoped variable may lead to confusing semantics. (W083)

How can I solve this ?

Answer 1

You could use a arrow function to stay in the same scope:

for (var evt in scope.tree.events) {
    if (scope.tree.events.hasOwnProperty(evt)) {
        var cb = scope.tree.events[evt];
        scope.tree.events[evt] = (...args) => {
            cb(...args);
            controller.$setDirty();
            scope.$evalAsync();
        };
        scope.tree.view.on(evt.indexOf('.') > 0 ? evt : evt + '.jstree',  scope.tree.events[evt]);
    }
}

Answer 2

This is how I solved my issue:

var cb = function(oldCb) {
    return function() {
        var result = oldCb.apply(this, arguments); 
        controller.$setDirty();
        scope.$evalAsync();
        return result;
    };
};

for (var evt in scope.tree.events) {
    if (scope.tree.events.hasOwnProperty(evt)) {
        var oldCb = scope.tree.events[evt];
        scope.tree.view.on(evt.indexOf('.') > 0 ? evt : evt + '.jstree',  cb(oldCb));
    }
}