fix: accept readonly arrays in fromFixture's parameters (#6)

* fix: accept readonly arrays in `fromFixture`'s parameters * refactor: remove redundant `undefined`
cartant · Oct 17, 2021 · 11a0792 · 11a0792
1 parent 397a0e9
commit 11a0792
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Showing 2 changed files with 19 additions and 12 deletions.
diff --git a/source/from-fixture-spec.ts b/source/from-fixture-spec.ts
@@ -283,7 +283,7 @@ describe("fromFixture", () => {
             `,
           },
         ],
-      }
+      } as const
     );
     expect(test).to.have.property("code", `const name = "alice";`);
     expect(test).to.have.property("errors");

diff --git a/source/from-fixture.ts b/source/from-fixture.ts
@@ -9,33 +9,33 @@ export function fromFixture<TMessageIds extends string>(
   fixture: string,
   invalidTestCase?: {
     output?: string;
-    suggestions?: eslint.SuggestionOutput<TMessageIds>[] | null | undefined;
+    suggestions?: readonly eslint.SuggestionOutput<TMessageIds>[] | null;
   }
 ): eslint.InvalidTestCase<TMessageIds, never>;
 
 export function fromFixture<
   TMessageIds extends string,
-  TOptions extends unknown[]
+  TOptions extends readonly unknown[]
 >(
   fixture: string,
   invalidTestCase: Omit<
     eslint.InvalidTestCase<TMessageIds, TOptions>,
     "code" | "errors"
   > & {
-    suggestions?: eslint.SuggestionOutput<TMessageIds>[] | null | undefined;
+    suggestions?: readonly eslint.SuggestionOutput<TMessageIds>[] | null;
   }
 ): eslint.InvalidTestCase<TMessageIds, TOptions>;
 
 export function fromFixture<
   TMessageIds extends string,
-  TOptions extends unknown[]
+  TOptions extends readonly unknown[]
 >(
   fixture: string,
   invalidTestCase: Omit<
     eslint.InvalidTestCase<TMessageIds, TOptions>,
     "code" | "errors"
   > & {
-    suggestions?: eslint.SuggestionOutput<TMessageIds>[] | null | undefined;
+    suggestions?: readonly eslint.SuggestionOutput<TMessageIds>[] | null;
   } = {}
 ): eslint.InvalidTestCase<TMessageIds, TOptions> {
   const { suggestions, ...rest } = invalidTestCase;
@@ -46,25 +46,28 @@ export function fromFixture<
 }
 
 function getSuggestions<TMessageIds extends string>(
-  suggestions: eslint.SuggestionOutput<TMessageIds>[] | null | undefined,
+  suggestions:
+    | readonly eslint.SuggestionOutput<TMessageIds>[]
+    | null
+    | undefined,
   indices: string | undefined
-): { suggestions?: eslint.SuggestionOutput<TMessageIds>[] } {
+) {
   if (!suggestions || indices === "") {
     return {};
   }
   if (indices === undefined) {
-    return { suggestions };
+    return { suggestions } as const;
   }
   return {
     suggestions: indices
       .split(/\s+/)
       .map((index) => suggestions[Number.parseInt(index, 10)]),
-  };
+  } as const;
 }
 
 function parseFixture<TMessageIds extends string>(
   fixture: string,
-  suggestions: eslint.SuggestionOutput<TMessageIds>[] | null | undefined
+  suggestions?: readonly eslint.SuggestionOutput<TMessageIds>[] | null
 ) {
   const errorRegExp =
     /^(?<indent>\s*)(?<error>~+)\s*\[(?<id>\w+)\s*(?<data>.*?)(?:\s*suggest\s*(?<indices>[\d\s]*))?\]\s*$/;
@@ -83,7 +86,11 @@ function parseFixture<TMessageIds extends string>(
         endLine: length,
         line: length,
         messageId: match.groups.id as TMessageIds,
-        ...getSuggestions(suggestions, match.groups.indices?.trim()),
+        // TODO: Remove typecast once https://github.com/typescript-eslint/typescript-eslint/pull/3844 is available.
+        ...(getSuggestions(
+          suggestions,
+          match.groups.indices?.trim()
+        ) as eslint.TestCaseError<TMessageIds>["suggestions"]),
       });
     } else {
       lines.push(line);