JS函数迭代通过对象并仅打印特定键的值返回undefined

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    {"isGroup":true, "key":-2, "text":"DM", "xy":"300 243.26562500000003"},
    {"key":100, "Data":"device", "group":-2},
    {"key":101, "Data":"name : Device1", "group":-2},
    {"key":102, "Data":"config", "group":-2},
    {"key":103, "Data":"interface", "group":-2},
    {"key":104, "Data":"Loopback", "group":-2},
    {"key":105, "Data":"name : {loopback-intf}", "group":-2},
    {"key":106, "Data":"description", "group":-2},
    {"key":107, "Data":"_tags : merge", "group":-2},
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    {"key":110, "Data":"address", "group":-2},
    {"key":111, "Data":"primary", "group":-2},
    {"key":112, "Data":"address : {ip-address}", "group":-2},
    {"key":113, "Data":"mask : 255.255.255.255", "group":-2},
    {"key":114, "Data":"_xmlns : https://someweb.org", "group":-2},
    {"key":115, "Data":"_tags : merge", "group":-2},
    {"key":116, "Data":"Loopback", "group":-2},
    {"key":117, "Data":"name : {loopback-intf}", "group":-2},
    {"key":118, "Data":"description", "group":-2},
    {"key":119, "Data":"_tags : merge", "group":-2},
    {"key":120, "Data":"__text : Loopback{loopback-intf}", "group":-2},
    {"key":121, "Data":"ip", "group":-2},
    {"key":122, "Data":"address", "group":-2},
    {"key":123, "Data":"primary", "group":-2},
    {"key":124, "Data":"address : {ip-address}", "group":-2},
    {"key":125, "Data":"mask : 255.255.255.255", "group":-2},
    {"key":126, "Data":"_xmlns : https://sometest.org", "group":-2},
    {"key":127, "Data":"_tags : merge", "group":-2},
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    {"key":1, "Data":"container v8_engine", "group":-1},
    {"key":2, "Data":"leaf-list cylinder-arrangement", "group":-1},
    {"key":3, "Data":"type string", "group":-1},
    {"key":4, "Data":"max-elements 8", "group":-1},
    {"key":5, "Data":"container other-parts", "group":-1},
    {"key":6, "Data":"list per-cylinder-parts", "group":-1},
    {"key":7, "Data":"leaf piston-diameter", "group":-1},
    {"key":8, "Data":"type uint32", "group":-1},
    {"key":9, "Data":"range 2000... 9000", "group":-1},
    {"key":10, "Data":"container valves", "group":-1},
    {"key":11, "Data":"leaf number", "group":-1},
    {"key":12, "Data":"list position", "group":-1},
    {"key":13, "Data":"type change", "group":-1}
     ],
      "linkDataArray": [ 
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    {"from":0, "to":5},
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    {"from":7, "to":8},
    {"from":7, "to":9},
    {"from":6, "to":10},
    {"from":10, "to":11},
    {"from":10, "to":12},
    {"from":5, "to":13},
    {"category":"Mapping", "from":4, "to":116},
    {"category":"Mapping", "from":6, "to":104},
    {"category":"Mapping", "from":9, "to":116},
    {"category":"Mapping", "from":12, "to":109}
     ]}
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