"" + 1 + 0 = "10" // (1)
"" - 1 + 0 = -1 // (2)
true + false = 1
6 / "3" = 2
"2" * "3" = 6
4 + 5 + "px" = "9px"
"$" + 4 + 5 = "$45"
"4" - 2 = 2
"4px" - 2 = NaN
" -9 " + 5 = " -9 5" // (3)
" -9 " - 5 = -14 // (4)
null + 1 = 1 // (5)
undefined + 1 = NaN // (6)
" \t \n" - 2 = -2 // (7)
- The addition with a string
"" + 1 converts 1 to a string: "" + 1 = "1", and then we have "1" + 0, the same rule is applied.
- The subtraction
- (like most math operations) only works with numbers, it converts an empty string "" to 0.
- The addition with a string appends the number
5 to the string.
- The subtraction always converts to numbers, so it makes
" -9 " a number -9 (ignoring spaces around it).
null becomes 0 after the numeric conversion.undefined becomes NaN after the numeric conversion.- Space characters are trimmed off string start and end when a string is converted to a number. Here the whole string consists of space characters, such as
\t, \n and a "regular" space between them. So, similarly to an empty string, it becomes 0.