Simple implementation of JS constellation calculation based on birthday month and date

JS simple implementation of Constellation calculation based on the birthday month and date this article describes the simple implementation of JS constellation calculation based on the birthday month and date. We will share this with you for your reference. The details are as follows:

I saw a js of a computing constellation written by someone else. If it was too long, I wrote it myself.

I think this function should be simplified enough :)

Input parameter: month [int] 1 ~ 12; day [int] 1 ~ 31.

// Calculate the Constellation Based on the month and date of the birthday. Function getAstro (month, day) {var s = ""; var arr = [20, 19, 21, 23, 23,23, 22,22]; return s. substr (month * 2-(day
   
If you search for the "date constellation function" on the Internet, except for my code or the code I reproduced, it is almost a long code, and I am afraid I cannot find code that is more concise than above.
However, the above three lines of code can be further streamlined and further improved:
// Calculate the Constellation Based on the month and date of the birthday. Function getAstro (m, d) {return "Libra Scorpio shooter ". substr (m * 2-(d <"102223444433 ". charAt (m-1)--19) * 2, 2 );}
   
Isn't it cool? There is only one line of code, and it is streamlined to the maximum extent.
A substr function and a charAt function are used above. If IE is not taken into account, the. charAt (S-1) function can be reduced to M-1].
If you do not need to output a constellation name but only need a digital index of the constellation, you can save the preceding string, which looks like this:
// Calculate the Constellation Based on the month and date of the birthday. Function getAstro (m, d) {return m-(d <"102223444433". charAt (S-1)--19); // output 0 ~ The number of 12, 0 indicates Capricorn, 1 indicates water bottle, and so on,..., 11 indicates shooter, and 12 indicates Capricorn .}
   
Write a test code to verify the Code:
// Calculate the Constellation Based on the month and date of the birthday. Function getAstro (m, d) {return "Libra Scorpio shooter ". substr (m * 2-(d <"102223444433 ". charAt (m-1)--19) * 2, 2);} // write a test function test (m, d) {document. writeln (m + "month" + d + "day" + getAstro (m, d);} // test (); // output: shooter test (); // output: Magic test (); // output: water bottle test ); // output: Pisces, September February 19
   
Appendix 12 constellation date comparison:
Capricorn (12/22-1/19), Aquarius (1/20-2/18), Pisces (2/19-3/20), Aries (3/21-4/20 ),
Taurus (4/21-5/20), Gemini (5/21-6/21), cancer (6/22-7/22), Leo (7/23-8/22 ),
VIRGO (8/23-9/22), Libra (9/23-10/22), Scorpio (10/23-11/21), Sagittarius (11/22-12/21)