How to Safely Invoke a JavaScript Function from a String Without Using `eval()`?

Invoking a Javascript Function Call from a String

This question addresses the challenge of converting a string representing a function call, such as "settings.functionName '(' t.parentNode.id ')'", into an actual function invocation. The goal is to execute the function as if the string had been directly entered as a function call, without using eval() which is discouraged due to security concerns.

Solution:

The provided solution suggests an alternative approach by leveraging the window object to obtain a reference to the function. Here's an updated and more detailed explanation:

<code class="javascript">// Store the function name extracted from the string as a variable
var functionName = settings.functionName;

// Check if the function exists in the global scope using window
if (typeof window[functionName] === 'function') {
  // If the function exists, invoke it with the specified argument
  window[functionName](t.parentNode.id);
}</code>

Example:

Consider the following settings object:

<code class="javascript">window.settings = {
  functionName: 'clickedOnItem',
};</code>

And the following function definition:

<code class="javascript">function clickedOnItem(nodeId) {
  // Function body
}</code>

Using the solution above, we can invoke the clickedOnItem function with the t.parentNode.id argument as follows:

<code class="javascript">// Extract the function name from the settings object
var functionName = settings.functionName;

// Check if the function exists in the global scope
if (typeof window[functionName] === 'function') {
  // Invoke the function with the specified argument
  window[functionName](t.parentNode.id);
}</code>

This method allows us to dynamically invoke functions based on a string representation without resorting to eval() or compromising security.

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