在循环中展开数组元素，向每个元素追加一个字符串

function appendStringToArray(arr, str) {
  var result = [];
  for (var i = 0; i < arr.length; i++) {
    var newString = arr[i] + str;
    result.push(newString);
  }
  return result;
}

// 示例用法
var originalArray = ["apple", "banana", "orange"];
var appendedArray = appendStringToArray(originalArray, "_fruit");
console.log(appendedArray);