Fix false positives for system rule (#16)

Author: ota-meshi

src/rules/system.ts

@@ -22,7 +22,7 @@ export default createRule("system", {
 
     const ignoreWarnings =
       context.settings?.["@ota-meshi/svelte"]?.ignoreWarnings
-    if (!Array.isArray(ignoreWarnings)) {
+    if (ignoreWarnings && !Array.isArray(ignoreWarnings)) {
       context.report({
         loc: { line: 1, column: 0 },
         message:
@@ -31,7 +31,7 @@ export default createRule("system", {
       return {}
     }
     const ignoreTests: ((ruleId: string) => boolean)[] = []
-    for (const ignoreWarning of ignoreWarnings) {
+    for (const ignoreWarning of ignoreWarnings || []) {
       if (typeof ignoreWarning !== "string") {
         context.report({
           loc: { line: 1, column: 0 },

tests/src/settings/ignore-warnings.ts

@@ -125,4 +125,38 @@ describe("ignore-warnings", () => {
       ],
     )
   })
+
+  it("without settings", async () => {
+    const code = `
+      {@html a+b}
+      {@debug a}
+      <script>
+        a+b;
+      </script>
+      `
+
+    const linter = new eslint.ESLint({
+      plugins: {
+        "@ota-meshi/svelte": plugin,
+      },
+      baseConfig: {
+        parser: require.resolve("svelte-eslint-parser"),
+        parserOptions: {
+          ecmaVersion: 2020,
+        },
+        plugins: ["@ota-meshi/svelte"],
+        rules: {
+          "@ota-meshi/svelte/system": "error",
+        },
+      },
+      useEslintrc: false,
+    })
+    const result = await linter.lintText(code, { filePath: "test.svelte" })
+    const messages = result[0].messages
+
+    assert.deepStrictEqual(
+      messages.map((m) => ({ ruleId: m.ruleId, line: m.line })),
+      [],
+    )
+  })
 })