fix: support empty Map and Set (jacob-ebey#26)

caprica · May 8, 2024 · 8ba3587 · 8ba3587
1 parent a72f7a7
commit 8ba3587
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Showing 2 changed files with 26 additions and 6 deletions.
diff --git a/src/flatten.ts b/src/flatten.ts
@@ -107,13 +107,21 @@ function stringify(this: ThisEncode, input: unknown, index: number) {
             input.source
           )},${JSON.stringify(input.flags)}]`;
         } else if (input instanceof Set) {
-          str[index] = `["${TYPE_SET}",${[...input]
-            .map((val) => flatten.call(this, val))
-            .join(",")}]`;
+          if (input.size > 0) {
+            str[index] = `["${TYPE_SET}",${[...input]
+              .map((val) => flatten.call(this, val))
+              .join(",")}]`;
+          } else {
+            str[index] = `["${TYPE_SET}"]`;
+          }
         } else if (input instanceof Map) {
-          str[index] = `["${TYPE_MAP}",${[...input]
-            .flatMap(([k, v]) => [flatten.call(this, k), flatten.call(this, v)])
-            .join(",")}]`;
+          if (input.size > 0) {
+            str[index] = `["${TYPE_MAP}",${[...input]
+              .flatMap(([k, v]) => [flatten.call(this, k), flatten.call(this, v)])
+              .join(",")}]`;
+          } else {
+            str[index] = `["${TYPE_MAP}"]`;
+          }
         } else if (input instanceof Promise) {
           str[index] = `["${TYPE_PROMISE}",${index}]`;
           deferred[index] = input;

diff --git a/src/turbo-stream.spec.ts b/src/turbo-stream.spec.ts
@@ -114,12 +114,24 @@ test("should encode and decode Map", async () => {
   expect(output).toEqual(input);
 });
 
+test("should encode and decode empty Map", async () => {
+  const input = new Map()
+  const output = await quickDecode(encode(input));
+  expect(output).toEqual(input);
+});
+
 test("should encode and decode Set", async () => {
   const input = new Set(["foo", "bar"]);
   const output = await quickDecode(encode(input));
   expect(output).toEqual(input);
 });
 
+test("should encode and decode empty Set", async () => {
+  const input = new Set();
+  const output = await quickDecode(encode(input));
+  expect(output).toEqual(input);
+});
+
 test("should encode and decode an Error", async () => {
   const input = new Error("foo");
   const output = await quickDecode(encode(input));