ladybird/Libraries/LibJS/Tests/string-concatenation.js

30 lines
1 KiB
JavaScript

test("adding strings", () => {
expect("" + "").toBe("");
expect("ab" + "").toBe("ab");
expect("" + "cd").toBe("cd");
expect("ab" + "cd").toBe("abcd");
});
test("adding strings with non-strings", () => {
expect("a" + 1).toBe("a1");
expect(1 + "a").toBe("1a");
expect("a" + {}).toBe("a[object Object]");
expect({} + "a").toBeNaN();
expect("a" + []).toBe("a");
expect([] + "a").toBe("a");
expect("a" + NaN).toBe("aNaN");
expect(NaN + "a").toBe("NaNa");
expect(Array(16).join([[][[]] + []][+[]][++[+[]][+[]]] - 1) + " Batman!").toBe(
"NaNNaNNaNNaNNaNNaNNaNNaNNaNNaNNaNNaNNaNNaNNaN Batman!"
);
});
test("adding strings with dangling surrogates", () => {
expect("\ud834" + "").toBe("\ud834");
expect("" + "\udf06").toBe("\udf06");
expect("\ud834" + "\udf06").toBe("𝌆");
expect("\ud834" + "\ud834").toBe("\ud834\ud834");
expect("\udf06" + "\udf06").toBe("\udf06\udf06");
expect("\ud834a" + "\udf06").toBe("\ud834a\udf06");
expect("\ud834" + "a\udf06").toBe("\ud834a\udf06");
});