前端js获取对象中的值

Question

M = {"type":"line","x1":429,"y1":135,"x2":374,"y2":182,"x3":432,"y3":220,"x4":559,"y4":306,"x5":605,"y5":191,"x6":458,"y6":100}
我该如何从对象M中获得x，y的所有的值以及最大值与最小值？然后将x，y的最大最小值赋值给M

Answer 1

    M = { "type": "line", "x1": 429, "y1": 135, "x2": 374, "y2": 182, "x3": 432, "y3": 220, "x4": 559, "y4": 306, "x5": 605, "y5": 191, "x6": 458, "y6": 100 }
    OM = { xmax: 0, xmin: 9999999, ymax: 0, ymin: 9999999 }
    for (attr in M) {
        var k = attr.charAt(0);
        if (OM[k + 'max'] !== undefined) OM[k + 'max'] = Math.max(OM[k + 'max'], M[attr]);
        if (OM[k + 'min'] !== undefined) OM[k + 'min'] = Math.min(OM[k + 'min'], M[attr]);
    }
    console.log(OM)
    //赋值，要改变键名称修改这里的代码
    for(attr in OM)M[attr]=OM[attr]