stringCharAt.js (1218B)
1 assertEq("foo".charAt(-123), ""); 2 assertEq("foo".charAt(-1), ""); 3 assertEq("foo".charAt(0), "f"); 4 assertEq("foo".charAt(1), "o"); 5 assertEq("foo".charAt(2), "o"); 6 assertEq("foo".charAt(3.4), ""); 7 assertEq("foo".charAt(), "f"); 8 assertEq("".charAt(), ""); 9 assertEq("".charAt(0), ""); 10 assertEq("abc\u9123".charAt(3), "\u9123"); // char without unit string 11 12 /* Inferred as string.charAt(int). */ 13 function charAt1(x) { 14 return "abc".charAt(x); 15 } 16 assertEq(charAt1(-1), ""); 17 assertEq(charAt1(0), "a"); 18 assertEq(charAt1(1), "b"); 19 assertEq(charAt1(2), "c"); 20 assertEq(charAt1(3), ""); 21 assertEq(charAt1(1234), ""); 22 23 /* Inferred as string.charAt(double). */ 24 function charAt2(x) { 25 return "abc".charAt(x); 26 } 27 assertEq(charAt2(-1.3), ""); 28 assertEq(charAt2(-0), "a"); 29 assertEq(charAt2(2), "c"); 30 assertEq(charAt2(2.3), "c"); 31 assertEq(charAt2(3.14), ""); 32 assertEq(charAt2(NaN), "a"); 33 34 /* Test ropes. */ 35 function charAt3(s, i) { 36 var s2 = "abcdef" + s + "12345"; 37 return s2.charAt(i); 38 } 39 assertEq(charAt3("abcdef", 14), "3"); 40 assertEq(charAt3("a" + "b", 1), "b"); 41 assertEq(charAt3("abcdefg" + "hijklmnop", 10), "e"); 42 43 /* Other 'this'. */ 44 var arr = [1, 2]; 45 arr.charAt = String.prototype.charAt; 46 assertEq(arr.charAt(1), ",");