fix: rule

Author: ota-meshi

src/rules/@typescript-eslint/no-unnecessary-condition.ts

@@ -307,6 +307,12 @@ export default createRule("@typescript-eslint/no-unnecessary-condition", {
       // Since typescript array index signature types don't represent the
       //  possibility of out-of-bounds access, if we're indexing into an array
       //  just skip the check, to avoid false positives
+      if (isArrayIndexExpression(node)) {
+        return
+      }
+
+      // When checking logical expressions, only check the right side
+      //  as the left side has been checked by checkLogicalExpressionForUnnecessaryConditionals
       //
       // Unless the node is nullish coalescing, as it's common to use patterns like `nullBool ?? true` to to strict
       //  boolean checks if we inspect the right here, it'll usually be a constant condition on purpose.

src/utils/ts-utils/index.ts

@@ -68,11 +68,8 @@ export function getTypeScript(context: RuleContext): TypeScript | undefined {
   try {
     // eslint-disable-next-line @typescript-eslint/no-require-imports -- ignore
     cacheTypeScript ??= require("typescript")
-    // eslint-disable-next-line @typescript-eslint/no-explicit-any -- ignore
-  } catch (e: any) {
-    if (e.code !== "MODULE_NOT_FOUND") {
-      throw e
-    }
+  } catch {
+    // ignore
   }
   return cacheTypeScript
 }

tests/fixtures/rules/@typescript-eslint/no-unnecessary-condition/invalid/example-errors.yaml

@@ -0,0 +1,4 @@
+- message: Unnecessary conditional, value is always falsy.
+  line: 4
+  column: 11
+  suggestions: null

tests/fixtures/rules/@typescript-eslint/no-unnecessary-condition/invalid/example-input.svelte

@@ -0,0 +1,10 @@
+<script lang="ts">
+  export let foo: number | null = null
+  /* ✗ BAD */
+  let b = foo || 42
+  /* ✓ GOOD */
+  $: a = foo || 42
+</script>
+
+<!-- ✓ GOOD -->
+{foo || 42}

tests/fixtures/rules/@typescript-eslint/no-unnecessary-condition/invalid/example-output.svelte

@@ -0,0 +1,10 @@
+<script lang="ts">
+  export let foo: number | null = null
+  /* ✗ BAD */
+  let b = foo || 42
+  /* ✓ GOOD */
+  $: a = foo || 42
+</script>
+
+<!-- ✓ GOOD -->
+{foo || 42}