Clarify, rename or remove map.loaded() method

[gpbmike]

mapbox-gl-js version: 39.1

Steps to Trigger Behavior

Add a canvas source / layer to the map.

Expected Behavior

map.loaded() eventually returns true.

Actual Behavior

map.loaded() never returns true.

Additional Details

I have created a codepen to demonstrate.

https://codepen.io/gpbmike/pen/NvqaZm

We're using map.loaded() to determine when certain actions can be performed that require the map to be loaded, see mapbox-gl-draw. We noticed that if you add a canvas source to the map, the map.loaded() will never change to true.

[mollymerp]

Thanks for the report @gpbmike –
I have confirmed that this is a bug, and map.loaded() isn't returning true because the source kicks off an infinite render loop.

Whoops! I spoke too soon. I didn't realize that CanvasSource defaults to animate=true. You can fix your example by adding animate = false (https://codepen.io/anon/pen/Evjbmv) but I do think we should figure out a way to check if animated sources are loaded 💭

[lbud]

Oo 🕵️‍♀️ @mollymerp I would guess this applies to video sources too, then.

[gpbmike]

Also what's the difference between map.loaded() and map.isStyleLoaded()?

[mollymerp]

@gpbmike map.loaded() checks that there are no pending source, tile, or style loads or updates and that the animation loop (triggered by any user interaction or programmatic map change) has finished. Because the animation loop never stops with animated canvas sources and video sources, that is blocking map.loaded() from returning true.

[mourner]

This seems to be more of an API naming/documentation issue that an actual bug, so I renamed/labeled it accordingly.

[mourner]

Closing in favor of #6708 to centralize the discussion there.