How Can I Safely Invoke JavaScript Functions by Name?

Invoking JavaScript Functions by Name

In JavaScript, accessing a function by its name as a string can be a convenient method for dynamic code execution. However, achieving this requires a cautious approach to avoid potential security vulnerabilities.

Solution:

Rather than employing the insecure eval function, which should be avoided unless absolutely necessary, a safer alternative is to use the following techniques:

1. Global Function Invocation:

To invoke a global function by its string name, use the following syntax:

window["functionName"](arguments);

This method works for functions that are declared at a global scope.

2. Namespaced Function Invocation (Complex Form):

To invoke a function that belongs to a namespace, use the following complex syntax:

window["My"]["Namespace"]["functionName"](arguments);

This syntax ensures that the function is accessed through its nested namespaces.

3. Namespaced Function Invocation (Convenience Function):

For simplified namespaced function invocation, consider using the following convenience function:

function executeFunctionByName(functionName, context /*, args */) {
  var args = Array.prototype.slice.call(arguments, 2);
  var namespaces = functionName.split(".");
  var func = namespaces.pop();
  for (var i = 0; i < namespaces.length; i++) {
    context = context[namespaces[i]];
  }
  return context[func].apply(context, args);
}

You can invoke a namespaced function using this convenience function as follows:

executeFunctionByName("My.Namespace.functionName", window, arguments);

This method allows you to flexibly specify the function's context, enabling invocation from different parts of your code.

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