javascript 字符串 数字反转 字母大小写互换

// 符串abcd123ABCD456 怎么转换为 ABCD321abcd654
// 数字要倒序 小写转大写, 大写转小写
Array.prototype.reverse = function() {
var tmp;
for (var i = 0, j = this.length - 1; i < j; i++, j--) {
tmp = this[i];
this[i] = this[j];
this[j] = tmp;
}
return this;
};function foo(s) {
var code, a = [],
b, last = 0; // 0 1:alpha 2:num for (var i = 0; i < s.length; i++) {
code = s.charCodeAt(i);
if ((97 <= code && code <= 97 + 26 - 1) || (65 <= code && code <= 65 + 26 - 1)) {
if (last !== 1) {
b = [], b.push(code), a.push(b);
} else {
a[a.length - 1].push(code);
}
last = 1;
} else if (48 <= code && code <= 48 + 9) {
if (last !== 2) {
b = [], b.push(code), a.push(b);
} else {
a[a.length - 1].push(code);
}
last = 2;
} else {
if (last !== 0) {
b = [], b.push(code), a.push(b);
} else {
a[a.length - 1].push(code);
}
last = 0;
}
} s = a.map(function(a) {
var c = a[0];
if (48 <= c && c <= 48 + 9) {
return a.reverse();
} else if (97 <= c && c <= 97 + 26 - 1) {
return a.map(function(c) {
return (c &= 0xdf);
});
} else if (48 <= c && c <= 48 + 26 - 1) {
return a.map(function(c) {
return (c |= 0x20);
});
}
return a;
}).map(function(a) {
return a.map(function(c) {
return String.fromCharCode(c);
}).join('');
}).join('');
return s;
}var s = "abcd123ABCD456";
console.log(foo(s));