Fix blank webview panels under Svelte 5 by enabling component API v4 compatibility#808
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chrisdp merged 1 commit intoMay 26, 2026
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…compatibility The webviews/package.json bump from svelte ^3.54.0 to ^5.55.8 in rokucommunity#794 left the Svelte-4-style class bootstrap in webviews/src/main.ts: new views[viewName]({ target: document.body }) Svelte 5 removes that API and throws `component_api_invalid_new` at runtime, so every "type": "webview" side panel (Roku Device View, Roku File System, Roku App Overlays, Roku Registry, Roku Commands, Roku Automation, Roku REPL, and SceneGraph Inspector) renders blank in 2.66.0. Setting compilerOptions.compatibility.componentApi: 4 in svelte.config.js restores the v4 class API at compile time. The bundle now emits the `if (new.target) return createClassComponent(...)` shim, so new Component(...) goes through Svelte 5's legacy adapter instead of throwing. This is a minimal, build-config-only change. A follow-up should migrate the bootstrap to Svelte 5's mount() API and clean up the remaining Svelte 5 warnings (self-closing non-void elements, on:click vs onclick, export let vs \$props()).
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confirmed the issue locally and the fix works in this PR. |
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Summary
webviews/src/main.ts:39still uses the Svelte-4 class API (new views[viewName]({ target: document.body })), which throwscomponent_api_invalid_newat runtime in Svelte 5.compilerOptions.compatibility.componentApi: 4inwebviews/svelte.config.js. The bundle now goes through Svelte 5's legacycreateClassComponentshim, so the existing bootstrap keeps working.Verified locally that
npm run buildsucceeds and the compiled bundle emits theif (new.target) return createClassComponent(...)legacy-adapter path.Test plan
npm run buildsucceeds.Follow-ups (out of scope for this PR)
webviews/src/main.tsto Svelte 5'smount(Component, { target })API.<div ... />,<vscode-checkbox ... />),on:click→onclick,export let→\$props().🤖 In help with Claude Code