转换JS中的复杂数据结构

Question

我正在开发一个需要从数据结构转换到另一个数据结构的项目。你会怎么做这个家伙？由此：

var json=[{"created_at":1385481173,"ranking":[["#OBAMA",88],["#TCOT",82]]},{"created_at":1385481233,"ranking":[["#OBAMA",86],["#TCOT",62]]},{"created_at":1385481293,"ranking":[["#OBAMA",82],["#TCOT",42]]},{"created_at":1385481353,"ranking":[["#OBAMA",67],["#TCOT",62]]},{"created_at":1385481413,"ranking":[["#OBAMA",88],["#TCOT",22]]}];

对此： http://pastebin.com/eTGWbARv

chart_data = [{
    "tag": "obama",
        "points": [{
        "created_at": 1385481173,
        rate: 27,
        tag: "obama"
    }, {
        "created_at": 1385481233,
        rate: 28,
        tag: "obama"
    }, {
        "created_at": 1385481293,
        rate: 23,
        tag: "obama"
    }, {
        "created_at": 1385481353,
        rate: 25,
        tag: "obama"
    }, {
        rate: 10,
        tag: "obama",
            "created_at": 1385481413
    }]
},

{
    "tag": "tcot",
        "points": [{
        "created_at": 1385481173,
        rate: 27,
        tag: "tcot"
    }, {
        "created_at": 1385481233,
        rate: 28,
        tag: "tcot"
    }, {
        "created_at": 1385481293,
        rate: 29,
        tag: "tco"
    }, {
        "created_at": 1385481353,
        rate: 23,
        tag: "tcot"

    }, {
        "created_at": 1385481413,
        rate: 25,
        tag: "tcot"
    }]
}];