Client-side bootstrapping

[vlukashov]

When developing a Vaadin app, I want to have a client-side API to start the application, so that I can start the app from my custom HTML file and defer Vaadin application start until after the first user interaction if needed. That allows starting a Vaadin app from client-side code (possibly offline).

vaadin/beverage-starter-flow#414: Use client-side bootstrapping in Beverage Buddy
#6130: Add NPM content for flow-client initialisation
#6132: Modify flow-client so as it can request server to initialize the UI
#6133: Create a flow.start() method to start a Flow app from the client-side
#6135: Create a IndexHtmlRequestHandler, able to return an index.html based on a template
#6136: Ensure bootstrapping compatibility with V14
#6138: Create a listener API for IndexHtmlRequestHandler
#6142: Support client-side bootstrapping in DevModeHandler
#6143: Create an integration test for flow.start
#6256: flow.start() should give server-side full control over the page
#6367: set client-side mode as the default in V15
#6431: CCDM: Provide a way for Flow to hook in to the index.html generation
#6442: CCDM: Supply default index.html and index.ts for Java-only use
#6443: index.html should not eagerly load dynamically imported chanks
#6468: prepare materials for a migration and client-side bootstrapping DX test
#6484: mark the BootstrapHandler API as depricated (in favor of the ClientIndexHandler API)
#6533: support @pwa annotations on an AppShell class
#6558: TestBench waitForVaadin should work when using client-side bootstrapping
#6574: add documentation for the flow.start() API
#6578: generated-flow-imports should have TS type definitions
#6584: create a BootstrapHandler to IndexHtmlResponseHandler migration doc
#6877: add default body styles in the generated index.html
#6883: make the comments in the generated webpack.config.js relevant for V15
#6894: add a 'this file is auto-generated' comment into the generated index.html / .ts file
#6911: @vaadin/flow-frontend/Flow.ts is deleted after running npm install
#6912: DevModeHandler should show progress while running webpack builds
#6938: allow customizing the index.html page with @meta annotations on an AppShell class
#6939: make UI optional in the PageConfigurator interface (deprecate and create another interface)
#6940: add an optional UI getter into IndexHtmlRequestListener
#6942: remove flow.start() in favor of always using flow.serverSideRoutes
#6971: support @inline, @bodysize and @Viewport annotations on an AppShell class
#6972: support the @Push annotation in V15 apps
#6975: warn when @meta, @pwa and other config annotations are misplaced

[haijian-vaadin]

beta is out