const arr = [{key:"address", value:"123 fake street"},{key:"loan", value:"no"},{key:"property", value:"no"}];
const object = arr.reduce(
  (obj, item) => Object.assign(obj, { [item.key]: item.value }), {});
console.log(object)
One more solution which is 99% faster (jsperf tested)
const object = arr.reduce((obj, item) => (obj[item.key] = item.value, obj) ,{});
and More simplest solution
// original
const arr = [ 
  {key:"address", value:"123 fake street"},
  {key:"loan", value:"no"},
  {key:"property", value:"no"}
];
//convert
const result = {};
for (var i = 0; i < arr.length; i++) {
  result[arr[i].key] = arr[i].value;
}
console.log(result);