преобразование типов

"" + 1 + 0 = "10"
"" - 1 + 0 = -1
true + false = 1
6 / "3" = 2
"2" * "3" = 6
4 + 5 + "px" = 9px
"$" + 4 + 5 = $45

"4" - 2 = 2

"4px" - 2 = 2

7 / 0 = NaN

"  -9\n" + 5 = "  -9\n5"
"  -9\n" - 5 = -14
5 && 2 = true

2 && 5 = true

5 || 0 = true

0 || 5 = true
null + 1 = 1
undefined + 1 = NaN
null == "\n0\n" = true
+null == +"\n0\n" = true

null == undefined - и всё