How to run a function in JavaScript every time a variable changes?

Question

Is there a way in JavaScript to have something like an event that listens to changes in a variable? so when its value is modified the event triggers and then I can call a function. To put this more into context I have a function which handles the html rendering of an array of objects, and I want that function to be called automatically every time the array is modified.

Thanks.

Answer 1

You could use setInterval to check for its value so many times a second, and save it into a separate variable. You can check each time whether the real variable is different from the other one. In that case, call the function.

It's a dirty trick, though.

Answer 2

I don't think what you ask is possible.

A solution might be to :

• encapsulate your data into a specific object
• access that data using a setter method of that object
• have that setter method both :
  • set the data
  • call your function

But it'll require you to rewrite a bit of your code.