Experiment to cleanup Terria start, and init sources

[nf-s]

Cleanup Terria start, and init sources

Fixes #6354

Main purpose of this PR is to simplify Terria.ts, Terria.start and InitSources.

Previously loadInitSources was getting called multiple times - at different stages of start and TerriaMap/index.js.

Now loadInitSources must be called explicitly after Terria.start()

I have also split up Terria.ts into

TerriaConfig.ts

• All interfaces - TerriaConfig, ConfigParameters, StartOptions, Analytics, HomeCameraInit

InitSource.ts

now handles all adding of init sources - none of these new functions call loadInitSources

• setupInitializationUrls -> addInitSourcesFromConfig
• interpretStartData -> addInitSourcesFromStartData
• updateApplicationUrl -> addInitSourcesFromUrl
• generateInitializationUrl -> generateInitializationUrl (private function)
• interpretHash -> interpretHash (private function)

As I have removed the following functions in Terria:

• updateFromStartData - instead use addInitSourcesFromStartData and then call terria.loadInitSources
• updateApplicationUrl - instead use addInitSourcesFromUrl and then call terria.loadInitSources

InitData.ts

now handles all applying of init data

• terria.applyInitData -> applyInitData
• terria.loadModelStratum -> loadModelStratum (private function)
• terria.pushAndLoadMapItems -> pushAndLoadMapItems (private function)

PickedFeatures.ts

• loadPickedFeatures -> loadPickedFeaturesFromJson in PickedFeatures.ts

Changes required to index.js in TerriaMap

See PR https://github.com/TerriaJS/TerriaMap/pull/603 for new load procedure:

• terria.start (await)
• Load plugins
• terria.loadInitSources (async)
• ... TerriaMap specifics - eg disclaimer
• render

https://github.com/TerriaJS/TerriaMap/blob/218633b1171b87f2f3c0520480c7a7ce24fabcb7/index.js#L62-L85

I have removed all Magda config functionality from Terria - this will need to be re-implemented in TerriaMap

Removed code is here https://gist.github.com/nf-s/4381b585fb2115a6e4d35dbcf77909c5

Other changes

• TSify updateApplicationOnMessageFromParentWindow
• updateApplicationOnHashChange and updateApplicationOnMessageFromParentWindow are now called in Terria.start
  • Added disableUpdateApplicationOnHashChange and disableUpdateApplicationOnMessageFromParentWindow to StartOptions
• Added getConfig to Terria StartOptions - this can be used to override fetching of Terria config through StartOptions.configUrl
• Terria.start will now await Internationalization init

Questions

Plugins

• What hooks are required?

updateApplicationOnHashChange and updateApplicationOnMessageFromParentWindow

• are they ever called on non-global window object?
• do we have maps where they aren't called?

Test links

Start data with huge GeoJSON file

Checklist

• [x] There are unit tests to verify my changes are correct or unit tests aren't applicable (if so, write quick reason why unit tests don't exist)
• [ ] I've updated relevant documentation in doc/.
• [x] I've updated CHANGES.md with what I changed.
• [ ] I've provided instructions in the PR description on how to test this PR.

[AnaBelgun]

without fixing this, it affects Stories loading for example (i.e. they might be slow to load due to GeoJSON files)

[steve9164]

How does this interact with plugin lifecycle?