Javascript populate array based on JSON object -

i have json object follows:

var testjson = [     { "asseta": "asset_a", "assetb": "asset_b" },     { "asseta": "asset_a", "assetb": "asset_b" },     { "asseta": "asset_c", "assetb": "asset_d" }, { "asseta": "asset_c", "assetb": "asset_e" }]; 

what want step through object , add repeating keys array, usedassets. here code far:

var usedassets = [];  (var key in testjson) {     console.log("current key: " + key + " " + "value: : " +  testjson[key].asseta);     console.log("current key: " + key + " " + "value: : " + testjson[key].assetb);      // check if in array     if ((isinarray(testjson[key].asseta, usedassets) || isinarray(testjson[key].assetb, usedassets))) {         break;     }     else {         usedassets.push(testjson[key].asseta);         usedassets.push(testjson[key].assetb);     } } console.log(usedassets);    function isinarray(value, array) {     return array.indexof(value) > -1; } 

however, output of array asset_a , asset_b. usedassets array should contain asset_a, asset_b, , asset_c. end goal able determine @ end of iteration, used asset_a once, asset_b once, , asset_c once.

basically, iterate elements of array , properties of object , count occurence.

var testjson = [{ "asseta": "asset_a", "assetb": "asset_b" }, { "asseta": "asset_a", "assetb": "asset_b" }, { "asseta": "asset_c", "assetb": "asset_d" }, { "asseta": "asset_c", "assetb": "asset_e" }],      count = {};    testjson.foreach(o => object.keys(o).foreach(k => count[o[k]] = (count[o[k]] || 0) + 1));    console.log(count);  console.log(object.keys(count).filter(k => count[k] > 1));

.as-console-wrapper { max-height: 100% !important; top: 0; }

es5

var testjson = [{ "asseta": "asset_a", "assetb": "asset_b" }, { "asseta": "asset_a", "assetb": "asset_b" }, { "asseta": "asset_c", "assetb": "asset_d" }, { "asseta": "asset_c", "assetb": "asset_e" }],      count = {};    testjson.foreach(function (o) {      object.keys(o).foreach(function (k) {          count[o[k]] = (count[o[k]] || 0) + 1;      });  });    console.log(count);  console.log(object.keys(count).filter(function (k) {      return count[k] > 1;  }));

.as-console-wrapper { max-height: 100% !important; top: 0; }