Besides :
true ? 1 : 0
is there any short trick which can "translate" True->1 and False->0 in Javascript ?
I've searched but couldn't find any alternative
What do you mean by "short trick" ?
answer : same as ~~6.6 is a trick forMath.floor
5 Answers
Lots of ways to do this
// implicit cast
+true; // 1
+false; // 0
// bit shift by zero
true >>> 0; // 1, right zerofill
false >>> 0; // 0
true << 0; // 1, left
false << 0; // 0
// double bitwise NOT
~~true; // 1
~~false; // 0
// bitwise OR ZERO
true | 0; // 1
false | 0; // 0
// bitwise AND ONE
true & 1; // 1
false & 1; // 0
// bitwise XOR ZERO, you can negate with XOR ONE
true ^ 0; // 1
false ^ 0; // 0
// even PLUS ZERO
true + 0; // 1
false + 0; // 0
// and MULTIPLICATION by ONE
true * 1; // 1
false * 1; // 0
You can also use division by 1, true / 1; // 1, but I'd advise avoiding division where possible.
Furthermore, many of the non-unary operators have an assignment version so if you have a variable you want converted, you can do it very quickly.
You can see a comparison of the different methods with this jsperf.
3 Comments
Royi Namir
can you elaborate on >>> ?
Paul S.
>>> is the Zero-fill right shift bitwise operator. x >>> y means "move every bit in x to the right by y, filling the now empty columns with 0". To choose y = 0 means you're not moving the bits anywhere, but it still does the cast.Paul S.
@RoyiNamir I think you'll find that is mainly due to the age of the machine I'm on. EDIT or not! I'm amazed at that. Firefox must have made some serious improvements to it's code.
Here is a more logical way Number()
Number(true) // = 1
Number(false) // = 0
2 Comments
micnguyen
Coming from a typed background, I prefer this way because it's explicitly clear about what you're getting back. I look at some of the examples in the accepted answer and I honestly couldn't tell you what would be the result 😅
Bilbonic
Used this with JQuery to get int value of checkbox and it worked perfectly. Thank you. var chkValue = Number($("#checkboxID").prop("checked")); // = 1 or 0
...or you can use +true and +false
Comments
You can use ~~boolean, where boolean is (obviously) a boolean.
~~true // 1
~~false // 0
Comments
To convert default switch value from boolean to numeric 0 or 1 to match your backend value.
0 should be converted into "false"
1 should be converted into "true"
This can be done using logic:
!!0 => false
!!1 => true
1 Comment
Yunnosch
I do not understand your explanation, half of which seems to be non-English. The code looks like it has the question in reverse, turning 0 into false and 1 into true. Please edit and try to improve, ideally according to How to Answer.
true + true + true == 3