fix: Don't break in attributeChangedCallback if $$component does not exist yet (#8701)

mimbrown · web-flow · commit 4f1063723e9c · 2023-06-14T21:33:17.000+02:00
Since the custom element class waits one tick before instantiating the `$$component` field, it's possibly undefined when `attributeChangedCallback` is called.
diff --git a/packages/svelte/src/runtime/internal/Component.js b/packages/svelte/src/runtime/internal/Component.js
@@ -287,7 +287,7 @@ if (typeof HTMLElement === 'function') {
 				this.$$props_definition,
 				'toProp'
 			);
-			this.$$component.$set({ [attr]: this.$$data[attr] });
+			this.$$component?.$set({ [attr]: this.$$data[attr] });
 		}
 
 		disconnectedCallback() {

Original file line number	Diff line number	Diff line change
`@@ -287,7 +287,7 @@ if (typeof HTMLElement === 'function') {`
`287`	`287`	`this.$$props_definition,`
`288`	`288`	`'toProp'`
`289`	`289`	`);`
`290`		`- this.$$component.$set({ [attr]: this.$$data[attr] });`
	`290`	`+ this.$$component?.$set({ [attr]: this.$$data[attr] });`
`291`	`291`	`}`
`292`	`292`
`293`	`293`	`disconnectedCallback() {`