如何用数组对象替换字符串中的子字符串？

function replaceSubstringsWithArray(str, substr, replacementArray) {
  var arr = str.split(substr);
  var newArr = [];
  
  for (var i = 0; i < arr.length; i++) {
    newArr.push(arr[i]);
    if (i < arr.length - 1) {
      newArr.push(replacementArray[i]);
    }
  }
  
  return newArr.join('');
}

// 示例用法
var originalString = "Hello, [name]! Today is [day].";
var substr = "[name]";
var replacementArray = ["John", "Monday"];

var replacedString = replaceSubstringsWithArray(originalString, substr, replacementArray);
console.log(replacedString);
// 输出: "Hello, John! Today is Monday."