test("simple escape characters", () => {
    expect("\n").toBe(String.fromCharCode(0x0a));
    expect("\r").toBe(String.fromCharCode(0x0d));
    expect("\t").toBe(String.fromCharCode(0x09));
    expect("\b").toBe(String.fromCharCode(0x08));
    expect("\f").toBe(String.fromCharCode(0x0c));
    expect("\v").toBe(String.fromCharCode(0x0b));
    expect("\0").toBe(String.fromCharCode(0x00));
    // Same in template literals.
    expect(`\n`).toBe(String.fromCharCode(0x0a));
    expect(`\r`).toBe(String.fromCharCode(0x0d));
    expect(`\t`).toBe(String.fromCharCode(0x09));
    expect(`\b`).toBe(String.fromCharCode(0x08));
    expect(`\f`).toBe(String.fromCharCode(0x0c));
    expect(`\v`).toBe(String.fromCharCode(0x0b));
    expect(`\0`).toBe(String.fromCharCode(0x00));
});

test("identity escapes", () => {
    expect("\'").toBe("'");
    expect('\"').toBe('"');
    expect("\\").toBe(String.fromCharCode(0x5c));
    expect("\a").toBe("a");
    expect("\q").toBe("q");
    // Same in template literals.
    expect(`\'`).toBe("'");
    expect(`\"`).toBe('"');
    expect(`\\`).toBe(String.fromCharCode(0x5c));
    expect(`\a`).toBe("a");
    expect(`\q`).toBe("q");
});

test("hex escapes", () => {
    expect("\x55").toBe("U");
    expect("X55").toBe("X55");
    expect(`\x55`).toBe("U");
    expect(`\X55`).toBe("X55");
    expect("\xff").toBe(String.fromCharCode(0xff));
    expect("\x00").toBe(String.fromCharCode(0x00));
    expect("'\\x'").not.toEval();
    expect("'\\x1'").not.toEval();
    expect("'\\xz'").not.toEval();
    expect("'\\xzz'").not.toEval();
    expect("'\\x🐞'").not.toEval();
});

test("unicode escapes", () => {
    expect("\u26a0").toBe("⚠");
    expect(`\u26a0`).toBe("⚠");
    expect("\u{1f41e}").toBe("🐞");
    expect(`\u{1f41e}`).toBe("🐞");
    expect("\u00ff").toBe(String.fromCharCode(0xff));
    expect("\u{0}").toBe(String.fromCharCode(0));
    expect("\u{41}").toBe("A");
    expect(`\u{41}`).toBe("A");
    expect("'\\u'").not.toEval();
    expect("'\\u1'").not.toEval();
    expect("'\\uf'").not.toEval();
    expect("'\\u123'").not.toEval();
    expect("'\\u123z'").not.toEval();
    expect("'\\uz'").not.toEval();
    expect("'\\uzz'").not.toEval();
    expect("'\\uzzzz'").not.toEval();
    expect("'\\u{'").not.toEval();
    expect("'\\u{}'").not.toEval();
    expect("'\\u{z}'").not.toEval();
    expect("'\\u🐞'").not.toEval();
});

describe("octal escapes", () => {
    test("basic functionality", () => {
        expect("\1").toBe("\u0001");
        expect("\2").toBe("\u0002");
        expect("\3").toBe("\u0003");
        expect("\4").toBe("\u0004");
        expect("\5").toBe("\u0005");
        expect("\6").toBe("\u0006");
        expect("\7").toBe("\u0007");
        // prettier-ignore
        expect("\8").toBe("8");
        // prettier-ignore
        expect("\9").toBe("9");
        expect("\128").toBe("\n8");
        expect("\141bc").toBe("abc");
        expect("f\157o\142a\162").toBe("foobar");
        expect("\123\145\162\145\156\151\164\171\117\123").toBe("SerenityOS");
    });

    test("syntax error in template literal", () => {
        expect("`\\123`").not.toEval();
    });

    test("syntax error in strict mode", () => {
        expect("'use strict'; '\\123'").not.toEval();
        expect('"use strict"; "\\123"').not.toEval();
        // Special case, string literal precedes use strict directive
        expect("'\\123'; 'use strict'").not.toEval();
        // Because of the non string statement in the middle strict mode is not enabled.
        expect("'\\123'; somethingElse; 'use strict'").toEval();
        expect("function f() { 5; '\\145'; function g() { 'use strict'; } }").toEval();
    });

    test("invalid octal escapes fail in strict mode", () => {
        expect("'use strict'; '\\8'").not.toEval();
        expect("'use strict'; '\\800'").not.toEval();
        expect("'use strict'; '\\9'").not.toEval();
        expect("'use strict'; '\\912'").not.toEval();
    });
});
