Object's properties.

irving

Hello, Where or how can I access the properties (methods) that can be passed to an object? For example, if I want to know which properties I can pass to the ellipse() object, where can I find this information? I am having a hard time finding out how to talk to my objects.

At the moment I am using console.dir(Object.keys(ellipse())); but what I cannot really make sense of what it is returning.

Any help is welcome. Apologies if the question has been asked before, I could not find the answer in the forum.

Thanks! Irving.

blindfish

In theory you should find all the information you need in the p5js reference. For example here's the entry for ellipse.

There's an obvious problem with using console.dir(Object.keys(ellipse())); to inspect Ellipse's (or any Object's) composition: it also includes inherited properties. If you look at the source you'll see that Ellipse exposes NO public properties/methods whatsoever... Note also that preceding an identifier with an _underscore is a convention for private properties/methods that you should avoid depending on in your code: and that's the case for the majority of Ellipse's inherited properties/methods...

GoToLoop

... if I want to know which properties I can pass to the ellipse() object, where can I find this information?

Look up its reference: http://p5js.org/reference/#/p5/ellipse

Some jargon explanation though: :-B

• ellipse()'s more correct term is function, even though functions are objects too.
• We don't pass properties but arguments to functions. Which in turn are assigned to their corresponding parameters.
• Functions in JS don't have formal signatures for their parameters and return types like we have in Java or C.
• We can pass as many arguments of any types and expect 1 returning value of any type.
• We can check a function's length property in order to know how many parameters were declared.
• However, given that JS doesn't force us to stick w/ that quantity, the actual number of parameters can vary depending on the internal implementation of each function.

GoToLoop

https://developer.Mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions

irving

Thank you, both, for your answers.

I apologize if I did not explain my question clearly. I am well aware of the reference page. The reason why I ask the question is because it seems to me that it lacks essential information as to which methods to pass the objects.

Regardless, it seems I was a bit confused, or just ignorant about the library.

It makes a lot of sense that ellipse() is a function, even if still an object. My guess is that I will need to create an object that holds the function.

Thanks again, your answers are very helpful.

GoToLoop

It makes a lot of sense that ellipse() is a function, even if still an object.

Gonna try to be more pedantic precise. Hope it doesn't make things messier to understand. ^#(^

• ellipse is itself a property of p5's prototype object.
• But b/c it is assigned to a function "object", we call it the ellipse() function.
• All functions & arrays are objects in JS. And if we look deeper, even numbers, boolean, strings, undefined, etc. are as well. @-)

irving

Hahaha, well, thank you. I do understand the concepts to a good level. It is helpful for me to see the source code and try to get the hang of it, even though I am not too familiarized with JS and the p5js libraries.

Thanks again for your time, I appreciate it!