LibJS: Implement Symbol.toStringTag

6 files changed, 45 insertions, 0 deletions

diff --git a/Libraries/LibJS/Tests/builtins/BigInt/BigInt.prototype.@@toStringTag.js b/Libraries/LibJS/Tests/builtins/BigInt/BigInt.prototype.@@toStringTag.js
new file mode 100644
index 0000000000..44812778a4
--- /dev/null
+++ b/Libraries/LibJS/Tests/builtins/BigInt/BigInt.prototype.@@toStringTag.js
@@ -0,0 +1,3 @@
+test("basic functionality", () => {
+    expect(BigInt.prototype[Symbol.toStringTag]).toBe("BigInt");
+});
diff --git a/Libraries/LibJS/Tests/builtins/JSON/JSON.@@toStringTag.js b/Libraries/LibJS/Tests/builtins/JSON/JSON.@@toStringTag.js
new file mode 100644
index 0000000000..5a1e51f7c6
--- /dev/null
+++ b/Libraries/LibJS/Tests/builtins/JSON/JSON.@@toStringTag.js
@@ -0,0 +1,4 @@
+test("basic functionality", () => {
+    expect(JSON[Symbol.toStringTag]).toBe("JSON");
+    expect(JSON.toString()).toBe("[object JSON]");
+});
diff --git a/Libraries/LibJS/Tests/builtins/Math/Math.@@toStringTag.js b/Libraries/LibJS/Tests/builtins/Math/Math.@@toStringTag.js
new file mode 100644
index 0000000000..69815a1499
--- /dev/null
+++ b/Libraries/LibJS/Tests/builtins/Math/Math.@@toStringTag.js
@@ -0,0 +1,4 @@
+test("basic functionality", () => {
+    expect(Math[Symbol.toStringTag]).toBe("Math");
+    expect(Math.toString()).toBe("[object Math]");
+});
diff --git a/Libraries/LibJS/Tests/builtins/Symbol/Symbol.prototype.@@toStringTag.js b/Libraries/LibJS/Tests/builtins/Symbol/Symbol.prototype.@@toStringTag.js
new file mode 100644
index 0000000000..c73e637fc4
--- /dev/null
+++ b/Libraries/LibJS/Tests/builtins/Symbol/Symbol.prototype.@@toStringTag.js
@@ -0,0 +1,3 @@
+test("basic functionality", () => {
+    expect(Symbol.prototype[Symbol.toStringTag]).toBe("Symbol");
+});
diff --git a/Libraries/LibJS/Tests/custom-@@toStringTag.js b/Libraries/LibJS/Tests/custom-@@toStringTag.js
new file mode 100644
index 0000000000..e297961e55
--- /dev/null
+++ b/Libraries/LibJS/Tests/custom-@@toStringTag.js
@@ -0,0 +1,26 @@
+test("inside objects", () => {
+    const o = {
+        [Symbol.toStringTag]: "hello friends",
+    };
+
+    expect(o.toString()).toBe("[object hello friends]");
+});
+
+test("inside classes", () => {
+    class A {
+        constructor() {
+            this[Symbol.toStringTag] = "hello friends";
+        }
+    }
+
+    const a = new A();
+    expect(a.toString()).toBe("[object hello friends]");
+});
+
+test("non-string values are ignored", () => {
+    const o = {
+        [Symbol.toStringTag]: [1, 2, 3],
+    };
+
+    expect(o.toString()).toBe("[object Object]");
+});
diff --git a/Libraries/LibJS/Tests/iterators/array-iterator.js b/Libraries/LibJS/Tests/iterators/array-iterator.js
index 117030ebdf..8f02845ebe 100644
--- a/Libraries/LibJS/Tests/iterators/array-iterator.js
+++ b/Libraries/LibJS/Tests/iterators/array-iterator.js
@@ -2,6 +2,11 @@ test("length", () => {
     expect(Array.prototype[Symbol.iterator].length).toBe(0);
 });
 
+test("@@toStringTag", () => {
+    expect([].values()[Symbol.toStringTag]).toBe("Array Iterator");
+    expect([].values().toString()).toBe("[object Array Iterator]");
+});
+
 test("same function as Array.prototype.values", () => {
     expect(Array.prototype[Symbol.iterator]).toBe(Array.prototype.values);
 });