From 8676dca4c03dd818e95a3fb36e01a6e6a0bd7e2b Mon Sep 17 00:00:00 2001
From: baseballyama <xydybaseball@gmail.com>
Date: Wed, 19 Mar 2025 20:35:39 +0900
Subject: [PATCH] fix(no-unused-props): resolve false positives on props with
 default values or $bindable usage

---
 .changeset/few-singers-marry.md                   |  5 +++++
 .../src/rules/no-unused-props.ts                  | 15 +++++++++++----
 .../no-unused-props/valid/bindable-input.svelte   |  9 +++++++++
 .../valid/default-value-input.svelte              | 14 ++++++++++++++
 4 files changed, 39 insertions(+), 4 deletions(-)
 create mode 100644 .changeset/few-singers-marry.md
 create mode 100644 packages/eslint-plugin-svelte/tests/fixtures/rules/no-unused-props/valid/bindable-input.svelte
 create mode 100644 packages/eslint-plugin-svelte/tests/fixtures/rules/no-unused-props/valid/default-value-input.svelte

diff --git a/.changeset/few-singers-marry.md b/.changeset/few-singers-marry.md
new file mode 100644
index 000000000..4e924dfd1
--- /dev/null
+++ b/.changeset/few-singers-marry.md
@@ -0,0 +1,5 @@
+---
+'eslint-plugin-svelte': patch
+---
+
+fix(no-unused-props): resolve false positives on props with default values or $bindable usage
diff --git a/packages/eslint-plugin-svelte/src/rules/no-unused-props.ts b/packages/eslint-plugin-svelte/src/rules/no-unused-props.ts
index 5de3133c0..2ea58fd87 100644
--- a/packages/eslint-plugin-svelte/src/rules/no-unused-props.ts
+++ b/packages/eslint-plugin-svelte/src/rules/no-unused-props.ts
@@ -369,10 +369,17 @@ export default createRule('no-unused-props', {
 				if (node.id.type === 'ObjectPattern') {
 					usedProps = getUsedPropertiesFromPattern(node.id);
 					if (usedProps.size === 0) return;
-					const identifiers = node.id.properties
-						.filter((p): p is TSESTree.Property => p.type === 'Property')
-						.map((p) => p.value)
-						.filter((v): v is TSESTree.Identifier => v.type === 'Identifier');
+					const identifiers: TSESTree.Identifier[] = [];
+					for (const p of node.id.properties) {
+						if (p.type !== 'Property') {
+							continue;
+						}
+						if (p.value.type === 'Identifier') {
+							identifiers.push(p.value);
+						} else if (p.value.type === 'AssignmentPattern' && p.value.left.type === 'Identifier') {
+							identifiers.push(p.value.left);
+						}
+					}
 					for (const identifier of identifiers) {
 						const paths = getUsedNestedPropertyNames(identifier);
 						usedPaths.push(...paths.map((path) => [identifier.name, ...path]));
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/no-unused-props/valid/bindable-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/no-unused-props/valid/bindable-input.svelte
new file mode 100644
index 000000000..ef2c5e990
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/no-unused-props/valid/bindable-input.svelte
@@ -0,0 +1,9 @@
+<script lang="ts">
+	interface Props {
+		selected: { value: string };
+	}
+
+	let { selected = $bindable() }: Props = $props();
+</script>
+
+<input type="text" bind:value={selected.value} />
diff --git a/packages/eslint-plugin-svelte/tests/fixtures/rules/no-unused-props/valid/default-value-input.svelte b/packages/eslint-plugin-svelte/tests/fixtures/rules/no-unused-props/valid/default-value-input.svelte
new file mode 100644
index 000000000..48d6887f4
--- /dev/null
+++ b/packages/eslint-plugin-svelte/tests/fixtures/rules/no-unused-props/valid/default-value-input.svelte
@@ -0,0 +1,14 @@
+<script lang="ts">
+	interface Props {
+		newTaskAttributes: { attribute: number; attribute2: string };
+	}
+
+	const { newTaskAttributes = { attribute: 0, attribute2: '' } }: Props = $props();
+</script>
+
+<div class="col-span-full">
+	<div>
+		{newTaskAttributes.attribute}
+		{newTaskAttributes.attribute2}
+	</div>
+</div>