如何动态添加属性到JSON数组

I have this JSON array

我有这个JSON数组

{"nodes":[
        {"type":"simple-node","left":500,"id":"node-start","content":"Start"},
        {"type":"simple-node","left":500,"id":"node-1","content":"Ironing"},
        {"type":"simple-node","left":500,"id":"node-end""content":"End"}
         ],

"connections":[
        {"start":"node-start","end":"node-1"},
        {"start":"node-4","end":"node-5"}
              ]
}
{"nodes":