assertFalse(StringUtil.isNumber(null));
        assertTrue(StringUtil.isNumber("0123456789"));
        assertFalse(StringUtil.isNumber("aaaBBBccc"));
        assertFalse(StringUtil.isNumber("０１２３４５６７８９"));
        assertFalse(StringUtil.isNumber(""));
        assertFalse(StringUtil.isNumber("01234abcdef"));
        assertFalse(StringUtil.isNumber("abcdef01234"));
    }

    /**
     *
     */

	// Output:
	// 10
	// 8
	// -1
}

func ExampleLastIndexFunc() {
	fmt.Println(strings.LastIndexFunc("go 123", unicode.IsNumber))
	fmt.Println(strings.LastIndexFunc("123 go", unicode.IsNumber))
	fmt.Println(strings.LastIndexFunc("go", unicode.IsNumber))
	// Output:
	// 5
	// 2
	// -1
}

func ExampleJoin() {
	s := []string{"foo", "bar", "baz"}
	fmt.Println(strings.Join(s, ", "))

	fmt.Printf("%t\n", unicode.IsDigit('৩'))
	fmt.Printf("%t\n", unicode.IsDigit('A'))
	// Output:
	// true
	// false
}

func ExampleIsNumber() {
	fmt.Printf("%t\n", unicode.IsNumber('Ⅷ'))
	fmt.Printf("%t\n", unicode.IsNumber('A'))
	// Output:
	// true
	// false
}

func ExampleIsLetter() {
	fmt.Printf("%t\n", unicode.IsLetter('A'))
	fmt.Printf("%t\n", unicode.IsLetter('7'))
	// Output:

  }

  @GwtIncompatible // Predicates.instanceOf
  public void testIsInstanceOf_subclass() {
    Predicate<@Nullable Object> isNumber = Predicates.instanceOf(Number.class);

    assertTrue(isNumber.apply(1));
    assertTrue(isNumber.apply(2.0f));
    assertFalse(isNumber.apply(""));
    assertFalse(isNumber.apply(null));
  }

  @GwtIncompatible // Predicates.instanceOf
  public void testIsInstanceOf_interface() {

  }

  @GwtIncompatible // Predicates.instanceOf
  public void testIsInstanceOf_subclass() {
    Predicate<@Nullable Object> isNumber = Predicates.instanceOf(Number.class);

    assertTrue(isNumber.apply(1));
    assertTrue(isNumber.apply(2.0f));
    assertFalse(isNumber.apply(""));
    assertFalse(isNumber.apply(null));
  }

  @GwtIncompatible // Predicates.instanceOf
  public void testIsInstanceOf_interface() {

func IsMark(r rune) bool {
	// There are no mark characters in Latin-1.
	return isExcludingLatin(Mark, r)
}

// IsNumber reports whether the rune is a number (category [N]).
func IsNumber(r rune) bool {
	if uint32(r) <= MaxLatin1 {
		return properties[uint8(r)]&pN != 0
	}
	return isExcludingLatin(Number, r)
}

// IsPunct reports whether the rune is a Unicode punctuation character
// (category [P]).

	// determine column widths and contents
	var widths []int
	var number []bool
	for _, line := range lines {
		for i, col := range line {
			if i < len(widths) {
				if len(col) > widths[i] {
					widths[i] = len(col)
				}
			} else {
				widths = append(widths, len(col))
				number = append(number, isnumber(col)) // first line determines column contents
			}
		}
	}

		if got != want {
			t.Errorf("%U incorrect: got %t; want %t", i, got, want)
		}
	}
}

func TestNumberLatin1(t *testing.T) {
	for i := rune(0); i <= MaxLatin1; i++ {
		got := IsNumber(i)
		want := Is(Number, i)
		if got != want {
			t.Errorf("%U incorrect: got %t; want %t", i, got, want)
		}
	}
}

func TestIsPrintLatin1(t *testing.T) {
	for i := rune(0); i <= MaxLatin1; i++ {
		got := IsPrint(i)

			return string(strconv.AppendInt(append([]byte(frame.File), ':'), int64(frame.Line), 10))
		}
	}

	return ""
}

func IsValidDBNameChar(c rune) bool {
	return !unicode.IsLetter(c) && !unicode.IsNumber(c) && c != '.' && c != '*' && c != '_' && c != '$' && c != '@'
}

// CheckTruth check string true or not
func CheckTruth(vals ...string) bool {
	for _, val := range vals {

//go:wasmimport gojs syscall/js.valueNew
//go:noescape
func valueNew(v ref, args []ref) (ref, bool)

func (v Value) isNumber() bool {
	return v.ref == valueZero.ref ||
		v.ref == valueNaN.ref ||
		(v.ref != valueUndefined.ref && (v.ref>>32)&nanHead != nanHead)
}

func (v Value) float(method string) float64 {
	if !v.isNumber() {
		panic(&ValueError{method, v.Type()})
	}
	if v.ref == valueZero.ref {
		return 0
	}