Preserve a JavaScript variable between component calls of the client-side code

Question

Is it possible to preserve a JavaScript variable between component calls of the client-side code?

For example, after a third party library in my component loads I am calling a function in the controller. That function creates a variable.

Then after a specific event is handled by the same component I am calling a function from the same controller as above. And here I would like to be able to access the variable.

Answer 1

You're allowed to store attributes on the global "window" object if you need to. Each component gets its own "SecureWindow" object, so your global variables can't affect other components.

However, the preferred method would be to set a private attribute:

<aura:attribute name="someAttr" type="someType" access="private" />

...

component.set("v.someAttr", someValue);

...

var someValue = component.get("v.someAttr");

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You can use whichever method makes the most sense. Also remember that you can use closures and Promises to temporarily store a value while chaining asynchronous callbacks.