Create Hashmap like implementation using java-script for json

Question

I am looking to create hashmap like array which will contain key and value derived from another array which has nested objects.

so i am trying the following code.

    var testhash={},data=[
      {
        "yang_type": "container",
        "name": "c1",
        "value": "",
        "children": [
          {
            "yang_type": "container",
            "name": "c2",
            "value": "",
            "children": [
              {
                "yang_type": "list",
                "name": "Car",
                "value": "",
                "children": [
                  {
                    "yang_type": "leaf",
                    "name": "wheels",
                    "value": "",
                    "children": [
                      {
                        "name": "max-elements",
                        "value": "4",
                        "children": [],
                        "yang_type": ""
                      }
                    ]
                  }
                ]
              },
              {
                "yang_type": "",
                "name": "text",
                "value": "4",
                "children": []
              }
            ]
          }
        ]
      }
    ];

 var k='';
                    function loop1(a, depth) {
                        var l,s='';
                        if(depth){s += '/';}
                        k=k+a.yang_type+a.name+a.value;
                        v=Array(depth + 1).join(s) + a.yang_type+a.name+a.value;
                        testhash.push(k:v);
                        //console.log(l);
                          //console.log(Array(depth + 1).join("/") + a.yang_type,a.name,a.value);
                          //hashServiceParams.push(Array(depth + 1).join("/") + a.yang_type,a.name,a.value);

                          Array.isArray(a.children) && a.children.forEach(function(child) {
                              loop1(child, depth + 1);
                          });
                        }
                    console.log(testhash);

The output, I am expecting is

{"containerc1":*,"containerc2":"containerc1/containerc2","listcar":"containerc1/containerc2/listcar","leafwheels":"containerc1/containerc2/listcar/leafwheels","max-elements":"containerc1/containerc2/listcar/leafwheels/max-elements","text4":"containerc1/text4"}

The above array will act as an hash map that contains key and value , where value stores the part of that data in the tree structure.

my code just calculates the depth and adds / to each level it moves down but i expect the output to be as shown above. Any recommendation coders ?

George Karanikas · Accepted Answer · 2016-06-23 09:09:24Z

1

The following should do the trick (use either version according to your needs):

ECMAScript 6:

function parseData(data, prefix) {
  let result = {};
  data.forEach(o => {
    const key = `${o.yang_type}${o.name}`;
    result[key] = prefix ? `${prefix}/${key}` : '*';
    if (o.children) {
      const newPrefix = prefix ? `${prefix}/${key}` : key;
      result = Object.assign(result, parseData(o.children, newPrefix));
    }
  });
  return result;
}

ECMAScript 5:

function shallowMerge(obj1,obj2){
  var obj3 = {};
  for (var attrname in obj1) { obj3[attrname] = obj1[attrname]; }
  for (var attrname in obj2) { obj3[attrname] = obj2[attrname]; }
  return obj3;
}

function parseData(data, prefix) {
  var result = {};
  data.forEach(function (o) {
    var key = '' + o.yang_type + o.name;
    result[key] = prefix ? prefix + '/' + key : '*';
    if (o.children) {
      var newPrefix = prefix ? prefix + '/' + key : key;
      result = shallowMerge(result, parseData(o.children, newPrefix));
    }
  });
  return result;
}

In order to use it you simply need to do the following:

let testhash = parseData(data);

This will populate the testHash with the result you need.

edited Jun 23, 2016 at 9:09

answered Jun 22, 2016 at 22:48

George Karanikas

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11 Comments

Nadvez Over a year ago

should this work as java script or should i include any specific libraries ?. Sorry this is the first time . I am hearing abt ecma script. Is there a way to have this convereted to JS ?

George Karanikas Over a year ago

ECMAScript is the "version" of javascript. The above snippet is written in version 6 which is not compatible with all browsers. I will update my answer with a version 5 one that will work without a problem.

Nadvez Over a year ago

Thank you for the answer .. Let me check it and Thank more :)

Nadvez Over a year ago

Thanks, This works like a charm but however if i would need to replace the output to {"0":*,"1":"containerc1/containerc2","2":"containerc1/containerc2/listcar","3":"containerc1/containerc2/listcar/leafwheels","4":"containerc1/containerc2/listcar/leafwheels/max-elements","5":"containerc1/text4"}

George Karanikas Over a year ago

Pass an optional number as argument to the function that will be incremented in each step. Then use it in the place of the key.

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