Merge arrays from object property in an object array [closed]

Give an array of objects as below:

var objArray = [{'key': 'key1', 'fields': [1, 2]}, {'key': 'key2', 'fields': [3, 4]}];

I would like to get an array of merged items from fields property and output should be 1, 2, 3, 4

I’ve tried to merge as below. I’m not satisfied with my solution and would like to get feedback’s and improve upon my solution. I’m new to JS and typescript. I believe there is better solution with features of ES6. Can someone help to improve my solution?

function mergeArraysFromObjectArray(objArray){
   let allFields = [];
    for (let obj of objArray) {
      for (let propt in obj) {
        if (obj.hasOwnProperty(propt) && propt === 'fields') {
          allFields = allFields.concat(obj[propt]);
        }
      }
    } 

  return allFields;
}

var objArray = [{'key': 'key1', 'fields': [1, 2]}, {'key': 'key2', 'fields': [3, 4]}];
let allMergedFields = mergeArraysFromObjectArray(objArray);

for(let i=0; i < allMergedFields.length; i++){
   console.log(allMergedFields[i]);  //prints - 1, 2, 3, 4
}

Answer

You can simply concat the array and create a new array inside a loop:

var objArray = [{'key': 'key1', 'fields': [1, 2]}, {'key': 'key2', 'fields': [3, 4]}];

var result = [];
for(var i=0; i<objArray.length; i++){
   result = result.concat(objArray[i].fields);
}

console.log(result);