1//The Math.sign() function returns either a positive or negative +/- 1,
2//indicating the sign of a number passed into the argument. If the number passed into
3//Math.sign() is 0, it will return a +/- 0. Note that if the number is positive,
4//an explicit (+) will not be returned.
5
6Math.sign(3); // 1
7Math.sign(-3); // -1
8Math.sign('-3'); // -1
9Math.sign(0); // 0
10Math.sign(-0); // -0
11Math.sign(NaN); // NaN
12Math.sign('foo'); // NaN
13Math.sign(); // NaN
14