tree.js

root = [{
	"id": 1,
	"name": "Yong",
	"phone": "010-2786-9902",
	"type": "sk",
	"childnode": [{
		"id": 11,
		"name": "echo",
		"phone": "010-3923-1333",
		"type": "kt",
		"childnode": [{
				"id": 115,
				"name": "hary",
				"phone": "010-2786-9302",
				"type": "sk",
				"childnode": [{
					"id": 1159,
					"name": "pobi",
					"phone": "010-9302-0009",
					"type": "kt",
					"childnode": [{
							"id": 11592,
							"name": "cherry",
							"phone": "010-1223-9932",
							"type": "lg",
							"childnode": []
						},
						{
							"id": 11595,
							"name": "solvin",
							"phone": "010-534-7843",
							"type": "sk",
							"childnode": []
						}
					]
				}]
			},
			{
				"id": 116,
				"name": "kim",
				"phone": "010-3796-1102",
				"type": "kt",
				"childnode": [{
					"id": 1168,
					"name": "hani",
					"phone": "010-1223-6713",
					"type": "sk",
					"childnode": [{
						"id": 11689,
						"name": "ho",
						"phone": "010-4434-4534",
						"type": "kt",
						"childnode": [{
								"id": 116890,
								"name": "wonsuk",
								"phone": "010-3434-1302",
								"type": "kt",
								"childnode": []
							},
							{
								"id": 1168901,
								"name": "chulsu",
								"phone": "010-3100-9841",
								"type": "sk",
								"childnode": []
							}
						]
					}]
				}]
			},
			{
				"id": 117,
				"name": "hong",
				"phone": "010-2786-9902",
				"type": "lg",
				"childnode": []
			}
		]
	}]
}]


function traverseTree(root) {
  var ret = [];
  var stack = [];
  var index = 0;

  for(item of root) {
    stack.push(item);
  }
  //console.log(stack);

  while(index < stack.length) {
    if(stack[index]["type"] == "sk") {
      //console.log(stack[index]["name"]);
      ret.push(stack[index]["name"]);
    }
    for(item of stack[index]["childnode"]) {
      stack.push(item);
    }
    index++;
  }

  return ret;

}

console.log(traverseTree(root));

const resultObj = {};

function parse(obj, spec) {
  var ret = [];
  var stack = [];
  var index = 0;

  for(item of root) {
    stack.push(item);
  }
  //console.log(stack);

  while(index < stack.length) {
    if(stack[index]["type"] == spec) {
      //console.log(stack[index]["name"]);
      ret.push(stack[index]["name"]);
    }
    for(item of stack[index]["childnode"]) {
      stack.push(item);
    }
    index++;
  }

  resultObj[spec] = ret;
}

parse(root, "sk");
console.log(resultObj.sk);
parse(root, "kt");
console.log(resultObj.kt);


var bufferstack = [];

function dfs(obj, name) {
  if(obj["type"] == name) {
    bufferstack.push(obj["name"]);
  }
  for(val of obj["childnode"]) {
    dfs(val, name);
  }
  return;
}

function mainDfs(arr, name) {
  for(val of arr) {
    dfs(val, name);
  }
}

function parse2(obj, spec) {
  mainDfs(obj, spec);
  resultObj[spec] = bufferstack;
  bufferstack = [];
}

parse2(root, "sk");
console.log(resultObj.sk);
parse2(root, "kt");
console.log(resultObj.kt);