使用对象查找数组中的min,max

Question

我有这个包含对象的数组:

var pts = [
    { "X": 52.67528921580262,  "Y": 8.373513221740723 },
    { "X": 52.6759657545252,   "Y": 8.374114036560059 },
    { "X": 52.682574466310314, "Y": 8.37256908416748  },
    { "X": 52.68356308524067,  "Y": 8.373942375183105 },
    { "X": 52.68293869694087,  "Y": 8.375487327575684 },
    { "X": 52.67685044320001,  "Y": 8.376259803771973 },
    { "X": 52.6756535071859,   "Y": 8.379607200622559 },
    { "X": 52.676017795531436, "Y": 8.382096290588379 },
    { "X": 52.68101344348877,  "Y": 8.380722999572754 },
    { "X": 52.68351105322329,  "Y": 8.383641242980957 },
    { "X": 52.68,              "Y": 8.389             }
];

如何找到最小值,最大值为X和最小值,最大值为Y？

Answer 1

你可以调用Math.min并Math.max传入一个只包含相关值的映射数组,如下所示:

function endProp( mathFunc, array, property ) {
    return Math[ mathFunc ].apply(array, array.map(function ( item ) {
        return item[ property ];
    }));
}

var maxY = endProp( "max", pts, "Y" ), // 8.389
    minY = endProp( "min", pts, "Y" ); // 8.37256908416748