如何在Node.js中使用变量获取Json值？

Question

我的json：

accountDetails = {
    "dev" : {
        "privatekey" : "0x20c269195291863633aa16fb073cce616a4646a2023e730c3e58a9da0b3764a6",
        "priv" :"20c269195291863633aa16fb073cce616a4646a2023e730c3e58a9da0b3764a6",
        "owner": "0x63c7b6633adc801f74a21599abfa6ae92d768a6d",
        "issuer" :"0x63c7B6633adC801F74a21599ABFA6AE92d768A6D",
        "receiver" : "0x14a18aec5076737ed651d295d38d0fa31ad515c9"
    },
    "rinkeby" : { 
        "privatekey" : "0xc1271a26fbb0291eaf17956e494dd12c6201d30c7c51d14972597e3a4dfe632",
        "priv" :"c1271a26fbb0291945477956e494dd12c6201d30c7c51d14972597e3a4dfe632",
        "owner": "0xC0c622CE70916eA0c0258b5EDc00ba4D5875dDA",
        "issuer" :"0x0e12e7455s1ccF124093e9A6D3a6fbCbaaCfb618",
        "receiver" : "0x5E5e1D3D5079da5D1693F614A58b22Ad972e66d1"
    }
}

假设我想访问accountDetals.dev形式的接收者的值，那么我会做accountDetails.dev.receiver，但是让我们说我想分配一个环境变量，该变量将选择从dev或rinkeby中选择一个值，即let env = "dev"如何访问相同的变量？

在这种情况下是accountDetails.dev.receiver == accountDetails.env.receiver吗？以及为什么？