使用标识符遍历JSON对象并使用标识符获取特定值

Question

Traverse through a JSON object which has nested arrays objects inside it . The label value is provided which is the identifier with which need to return the associated level metrics value . If the label is found in the 2nd level find the metrics at the second level and it should be returned

I couldn't get the logic on how to traverse through an object and return the specific value

function getMetrics(arr, label) {

  for (let i = 0; i < arr.length; i++) {
    if (arr[i].label === label) {
      return arr[i].metricsValue;
    } else if (arr[i].children) {
      return getMetrics(arr[i].children, label);
    }
  }

  return "Not found";
}
const selectedMetrics = getMetrics(dataObj.series, '1');

Consider the JSON object with children specifies the sub level of the current level .

const dataObj = {
  series: [
    {
      label: "A",
      metricsValue: "ma",
      children: [
        {
          label: "A-B",
          value: 6,
          metricsValue: "ma-mb"
        },
        {
          label: "A-B-C",
          metricsValue: "ma-mb-mc",
          children: [
            {
              label : "A-B-C-D",
              value: 6,
              metricsValue: "ma-mb-mc-md"
            }
          ]
        }
      ]
    },
    {
      label: "1",
      metricsValue: "m1",
    }
  ]
};

Expected Result : When the input is "1", it should return

selectedMetrics= "m1"

Input : "ABCD"

selectedMetrics= "ma-mb-mc-md"

Answer 1

You can perform a Depth first search (DFS) or Breadth first search (BFS) to find metricValues at any level.

Here I'm using DFS to find the required value. This works for data with any nested levels.

 const dataObj = { series: [ { label: "A", metricsValue: "ma", children: [ { label: "AB", value: 6, metricsValue: "ma-mb" }, { label: "ABC", metricsValue: "ma-mb-mc", children: [ { label: "ABCD", value: 6, metricsValue: "ma-mb-mc-md" } ] } ] }, { label: "1", metricsValue: "m1"} ] }; function getMetrics(arr, label) { var result; for (let i = 0; i < arr.length; i++) { if (arr[i].label === label) { return arr[i].metricsValue; } else if (arr[i].children) { result = getMetrics(arr[i].children, label); if (result) { return result; } } } return null; } console.log("selectedMetrics for 'A' = " + getMetrics(dataObj.series, 'A')); console.log("selectedMetrics for 'AB' = " + getMetrics(dataObj.series, 'A-B')); console.log("selectedMetrics for 'ABC' = " + getMetrics(dataObj.series, 'AB-C')); console.log("selectedMetrics for 'ABCD' = " + getMetrics(dataObj.series, 'ABC-D')); console.log("selectedMetrics for '1' = " + getMetrics(dataObj.series, '1')); 

Answer 2

Your'e passing in the value, so use it instead of the string & you're not accessing the children nodes.

 for(var i=0; i< arr.length;i++){
        const x = arr[i];
        if (x.children.label === value) {
          console.log(x.metricValue)
        }else{
          x.forEach(element => {
            if (element.children.label === value) {
              console.log(element.metricValue)
            }else{
              element.forEach(secondEl =>{
                if (secondEl.children.label === value) {
                  console.log(secondEl.metricValue)
                }
              })
            }
          });
        }
      }

You can create a more elegant way of iterating around the children nodes but that may help you out