Handle the no match case. (microbit-foundation#460)

microbit-matt-hillsdon · web-flow · commit c037a61fc05b · 2022-01-24T10:27:01.000Z
Previously returned truncated first/last/only text extract.
diff --git a/src/documentation/extracts.test.ts b/src/documentation/extracts.test.ts
@@ -25,6 +25,9 @@ describe("contextExtracts", () => {
       { type: "match", extract: "match" },
     ]);
   });
+  it("no match", () => {
+    expect(contextExtracts([], "match", 3)).toEqual([]);
+  });
   it("splits text between matches", () => {
     expect(
       contextExtracts(
diff --git a/src/documentation/extracts.ts b/src/documentation/extracts.ts
@@ -60,6 +60,9 @@ export const contextExtracts = (
   text: string,
   context: number = 10
 ): Extract[] => {
+  if (positions.length === 0) {
+    return [];
+  }
   const extracts = fullStringExtracts(positions, text);
   return extracts.map((e, index) => {
     const length = e.extract.length;
