JS实现Json查询的方法实例_javascript技巧

var count = 0;

for (var i = 0; i < queryArr.length; i++) {

var e = queryArr[i];

if ($express) {
count++;
}
}

return count;
}

/*
* 模板创建函数
*/
var createIntance = function (exp) {
var fun = template.toString().replace("$express", exp).toString();
return eval("0," + fun);
}

var testTodo = function () {

var testArr = [
{ name: "张三", age: 20 },
{ name: "李四", age: 25 },
{ name: "王二麻子", age: 28 },
{ name: "小张", age: 30 }
];

var func = createIntance("e.age>=25");

alert(func(testArr));
}

/****************** JS 实现 JSON查询 **********************/

// 定义常用的函数
var len = function (s) { return s.length; }
var left = function (s, n) { return s.substr(0, n); }
var right = function (s, n) { return s.substr(-n); }
var index = function (s, find) { return s.indexOf(find) + 1; }

// 扩展原型方法
var _proto = Object.prototype;

// 缓存,解决快速查找
var _cache = {};

// 扩展运算符
var _alias = [
/@/g, "_e.",
/AND/gi, "&&",
/OR/gi, "||",
/<>/g, "!=",
/NOT/gi, "!",
/([^=<>])=([^=]|$)/g, '$1==$2'
];

var _rQuote = /""/g;
var _rQuoteTemp = /!~/g;

// 编译
var _complite = function (code) {
return eval("0," + code);
}

// 将扩展符号转换成标准的JS符号
var _interpret = function (exp) {
exp = exp.replace(_rQuote,"!~");
var arr = exp.split('"');
var i, n = arr.length;
var k = _alias.length;

for (var i = 0; i < n; i += 2) {
var s = arr[i];
for (var j = 0; j < k; j += 2) {
if (index(s, _alias[j]) > -1) {
s = s.replace(_alias[j], _alias[j + 1]);
}
}
arr[i] = s;
}

for (var i = 1; i < n; i += 2) {
arr[i] = arr[i].replace(_rQuoteTemp, '\\"');
}
return arr.join('"');
}

// 定义模函数
var _templ = function (_list) {
var _ret = [];
var _i = -1;

for (var _k in _list) {
var _e = _list[_k];
if (_e != _proto[_k]) {
if ($C) {
_ret[++_i] = _e;
}
}
}
return _ret;
} .toString();

// 扩展查询的方法
_proto.Query = function (exp) {
if (!exp) {
return [];
}

var fn = _cache[exp];

try {
if (!fn) {
var code = _interpret(exp);
code = _templ.replace("$C", code);
fn = _cache[exp] = _complite(code);
}
return fn(this);
} catch (e) {
return [];
}
}

var doTest = function () {

var heros = [
// 名============攻=====防=======力量====敏捷=====智力====
{name: '冰室女巫', DP: 38, AP: 1.3, Str: 16, Dex: 16, Int: 21 },
{ name: '沉默术士', DP: 39, AP: 1.1, Str: 17, Dex: 16, Int: 21 },
{ name: '娜迦海妖', DP: 51, AP: 6.0, Str: 21, Dex: 21, Int: 18 },
{ name: '赏金猎人', DP: 39, AP: 4.0, Str: 17, Dex: 21, Int: 16 },
{ name: '剧毒术士', DP: 45, AP: 3.1, Str: 18, Dex: 22, Int: 15 },
{ name: '光之守卫', DP: 38, AP: 1.1, Str: 16, Dex: 15, Int: 22 },
{ name: '炼金术士', DP: 49, AP: 0.6, Str: 25, Dex: 11, Int: 25 }
//...
];

var match = heros.Query('@Str>20 AND @Dex>20');
ShowResult(match[0]);

// 查询：“士”结尾的
// 结果：沉默术士,剧毒术士,炼金术士
var match = heros.Query('right(@name,1)="士"');
ShowResult(match[0]);
}

function ShowResult(result) {
alert(result.name + " " + result.DP + " " + result.AP + " " + result.Str + " " + result.Dex + " " + result.Int);
}