如何从节点红色中的json中提取多个值

问题描述

我正在尝试从多个JSON数组中提取多个值以创建饼图。

下面的函数只能获取一个值，但是我想要从这些数组获取所有值，例如，标记应返回“未标记”，“ HK_Online”，“ HK_Order / Change address”，但仅返回“ HK_Online”。

我的功能节点

var value = msg.payload.lines[0][1].value;
var tag = msg.payload.lines[1][0].value;

msg.topic = tag;
msg.payload = value;
return msg;

JSON数据

{
  "axes": {
    "x": [
      { "name": "Tag","type": "string" },{ "name": "Total","type": "number" },{ "name": "Percentage","type": "percent" },{ "name": "Delta","type": "delta" }
    ]
  },"lines": [
    [
      { "type": "string","value": "Untagged" },{ "type": "number","value": 1 },{ "type": "percent","value": 20 },{ "type": "delta","value": 100 }
    ],[
      { "type": "string","value": "HK_Online" },"value": 4 },"value": 80 },"value": "HK_Order/Change address" },"value": 100 }
    ]
  ]
}

解决方法

您可以使用map方法从lines数组创建新数组

let lines = msg.payload.lines

let tag = lines.map(item => item[0].value)
let value = lines.map(item => item[1].value)

javascript node-red