LibJS: Implement most of String.prototype.replace

Userland/Libraries/LibJS/Tests/builtins/String/String.prototype.replace.js

@@ -0,0 +1,104 @@
+test("invariants", () => {
+    expect(String.prototype.replace).toHaveLength(2);
+});
+
+test("error cases", () => {
+    [null, undefined].forEach(value => {
+        expect(() => {
+            value.replace("", "");
+        }).toThrow(TypeError);
+    });
+});
+
+test("basic string replacement", () => {
+    expect("".replace("", "")).toBe("");
+    expect("".replace("a", "")).toBe("");
+    expect("".replace("", "a")).toBe("a");
+
+    expect("a".replace("a", "")).toBe("");
+    expect("a".replace("a", "b")).toBe("b");
+    expect("aa".replace("a", "b")).toBe("ba");
+    expect("ca".replace("a", "b")).toBe("cb");
+});
+
+test("convertible string replacement", () => {
+    expect("123".replace(2, "x")).toBe("1x3");
+    expect("123".replace("2", 4)).toBe("143");
+    expect("123".replace(2, 4)).toBe("143");
+});
+
+test("functional string replacement", () => {
+    expect(
+        "a".replace("a", function () {
+            return "b";
+        })
+    ).toBe("b");
+    expect("a".replace("a", () => "b")).toBe("b");
+
+    expect(
+        "abc".replace("b", (search, position, string) => {
+            expect(search).toBe("b");
+            expect(position).toBe(1);
+            expect(string).toBe("abc");
+            return "x";
+        })
+    ).toBe("axc");
+});
+
+test("basic regex replacement", () => {
+    expect("".replace(/a/, "")).toBe("");
+    expect("a".replace(/a/, "")).toBe("");
+
+    expect("abc123def".replace(/\D/, "*")).toBe("*bc123def");
+    expect("123abc456".replace(/\D/, "*")).toBe("123*bc456");
+    expect("abc123def".replace(/\D/g, "*")).toBe("***123***");
+    expect("123abc456".replace(/\D/g, "*")).toBe("123***456");
+});
+
+test("functional regex replacement", () => {
+    expect(
+        "a".replace(/a/, function () {
+            return "b";
+        })
+    ).toBe("b");
+    expect("a".replace(/a/, () => "b")).toBe("b");
+
+    expect(
+        "abc".replace(/\D/, (matched, position, string) => {
+            expect(matched).toBe("a");
+            expect(position).toBe(0);
+            expect(string).toBe("abc");
+            return "x";
+        })
+    ).toBe("xbc");
+
+    expect(
+        "abc".replace(/\D/g, (matched, position, string) => {
+            expect(matched).toBe(string[position]);
+            expect(position <= 2).toBeTrue();
+            expect(string).toBe("abc");
+            return "x";
+        })
+    ).toBe("xxx");
+
+    expect(
+        "abc".replace(/(\D)/g, (matched, capture1, position, string) => {
+            expect(matched).toBe(string[position]);
+            expect(capture1).toBe(string[position]);
+            expect(position <= 2).toBeTrue();
+            expect(string).toBe("abc");
+            return "x";
+        })
+    ).toBe("xxx");
+
+    expect(
+        "abcd".replace(/(\D)b(\D)/g, (matched, capture1, capture2, position, string) => {
+            expect(matched).toBe("abc");
+            expect(capture1).toBe("a");
+            expect(capture2).toBe("c");
+            expect(position).toBe(0);
+            expect(string).toBe("abcd");
+            return "x";
+        })
+    ).toBe("xd");
+});