Javascript method for Json query _ javascript skills

I have read a template class written by Daniel to implement Json. Today I am trying to write it myself. Fortunately, I still remember some things and thought it was clear. Directly Writing the code is actually very simple. The first part of my code is simple implementation of how to use JS to write templates, and the second is to implement an extension of JSON query.

Json query will be available in the future.

The Code is as follows:

/*
* Define template Functions
*/
Var template = function (queryArr ){

Var count = 0;

For (var I = 0; I <queryArr. length; I ++ ){

Var e = queryArr [I];

If ($ express ){
Count ++;
}
}

Return count;
}

/*
* Template creation Function
*/
Var createIntance = function (exp ){
Var fun = template. toString (). replace ("$ express", exp). toString ();
Return eval ("0," + fun );
}

Var testTodo = function (){

Var testArr = [
{Name: "Zhang San", age: 20 },
{Name: "Li Si", age: 25 },
{Name: "Wang Erma zi", age: 28 },
{Name: "Xiao Zhang", age: 30}
];

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

Alert (func (testArr ));
}

/***************** JSON query in JS ***************** *****/

// Define common functions
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 ;}

// Extended Prototype Method
Var _ proto = Object. prototype;

// Cache for quick search
Var _ cache = {};

// Extension operator
Var _ alias = [
/@/G, "_ e .",
/AND/gi ,"&&",
/OR/gi, "| ",
/<>/G ,"! = ",
/NOT/gi ,"! ",
/([^ = <>]) = ([^ =] | $)/G, '$1 = $2'
];

Var _ rQuote =/""/g;
Var _ rQuoteTemp = /!~ /G;

// Compile
Var _ complite = function (code ){
Return eval ("0," + code );
}

// Convert the extension symbol into a standard JS symbol
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 ('"');
}

// Define a model function
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 ();

// Extended Query Method
_ 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 = [
// Name = intelligence ====
{Name: 'ice witch ', DP: 38, AP: 1.3, Str: 16, Dex: 16, Int: 21 },
{Name: 'silent locker', DP: 39, AP: 1.1, Str: 17, Dex: 16, Int: 21 },
{Name: 'naga haidao ', DP: 51, AP: 6.0, Str: 21, Dex: 21, Int: 18 },
{Name: 'bounty hunter ', DP: 39, AP: 4.0, Str: 17, Dex: 21, Int: 16 },
{Name: 'highly toxic wareer', DP: 45, AP: 3.1, Str: 18, Dex: 22, Int: 15 },
{Name: 'guard of light ', DP: 38, AP: 1.1, Str: 16, Dex: 15, Int: 22 },
{Name: 'authorization', DP: 49, AP: 0.6, Str: 25, Dex: 11, Int: 25}
//...
];

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

// Query:
// Result: silent locks, highly toxic locks, and alchemy locks
Var match = heros. Query ('Right (@ name, 1) = "Shi "');
ShowResult (match [0]);
}

Function ShowResult (result ){
Alert (result. name + "" + result. DP + "" + result. AP + "" + result. str + "" + result. dex + "" + result. int );
}

The code is like this. You are welcome to come up with new ideas. Let's expand together