Vanilla JavaScript Dynamically Calling a Function

Vanilla JavaScript Dynamically Calling a Function

Chris Bongers
·Jul 18, 2020·

2 min read

Have you ever had the scenario where you needed to call a function, but based on a variable?

In my most recent use case, I have an area of dynamic modules and loop over them; then, if I find one of these, I want to call the function dynamically.

So how do we go about this?

Defining our Functions

First, let's start by making our functions.

function customClick(button) {
  button.addEventListener('click', function(event) {
    alert('custom click');
  });
}

function customUppercase(input) {
  input.addEventListener('keyup', function() {
    input.value = input.value.toUpperCase();
  });
}

Not very exciting functions but good enough to test with.

For this we are going to use the following HTML

<input type="text" data-module="customUppercase" /> <br /><br />
<button type="submit" data-module="customClick">Done</button>

JavaScript Dynamically Calling a Function

Ok, let's start by defining our array of custom objects.

var options = ['Click', 'Uppercase'];

We will now loop over these:

for (var i = 0; i < options.length; i++) {
  console.log(options[i]);
}

Within the modules we need to get all the types that have the data-module we are passing:

for (var i = 0; i < options.length; i++) {
  var items = document.querySelectorAll('[data-module="custom' + options[i] + '"]');
  for (var j = 0; j < items.length; j++) {
    // Call function
  }
}

Now, we need to call the function dynamically!

for (var i = 0; i < options.length; i++) {
  var items = document.querySelectorAll('[data-module="custom' + options[i] + '"]');
  for (var j = 0; j < items.length; j++) {
    this['custom' + options[i]](items[j]);
  }
}

That's it! Have a shot at this Codepen.

Thank you for reading, and let's connect!

Thank you for reading my blog. Feel free to subscribe to my email newsletter and connect on Facebook or Twitter

Did you find this article valuable?

Support Chris Bongers by becoming a sponsor. Any amount is appreciated!

See recent sponsors Learn more about Hashnode Sponsors
 
Share this