Add several properties based on the original array property values

the reference answer GPT ᴼ ᴾ ᴱ ᴺ ᴬ ᴵ < br / > can be done according to the following steps:

Traverses the arr1 array, generates the corresponding Type attribute value, and merges the value of Type to generate a new attribute name.

Walk through the arr2 array, adding the newly generated property name to the array object.

Combine the chr_ attribute name in arr1 with the value of Type to generate a new attribute name, add it to the arr2 array object, and assign it as an empty string.

Here is the code implementation:

let arr1 = [
  {
    Num: "0001",
    chr_Beijing: "xx",
    chr_Shanghai: "xx"
  },
  {
    Num: "0002",
    chr_Beijing: "xx",
    chr_Shanghai: "xx"
  },
   {
    Num: "0003",
    chr_Beijing: "xx",
    chr_Shanghai: "xx"
  }
]

let arr2 = [
  {
    Num: "0001",
    Type: "T1",
    T1_Beijing: "",
    chr_Beijing: "xx",
    T1_Shanghai: "",
    chr_Shanghai: "xx"  
  },
  {
    Num: "0002",
    Type: "T2",
    T2_Beijing: "",
    chr_Beijing: "xx",
    T2_Shanghai: "",
    chr_Shanghai: "xx"
  },
  {
    Num: "0003",
    Type: "T3",
    T3_Beijing: "",
    chr_Beijing: "xx",
    T3_Shanghai: "",
    chr_Shanghai: "xx"
  }
]

for (let i = 0; i < arr1.length; i++) {
  let num = arr1[i].Num.replace(/^0+/, ''); // 去掉前导0的整数
  let type = "T" + num;
  let keys = Object.keys(arr1[i]);
  for (let j = 0; j < keys.length; j++) {
    let key = keys[j];
    if (key.indexOf("chr_") === 0) {
      let city = key.replace("chr_", "");
      let newKey = type + "_" + city;
      arr2[i][newKey] = "";
    }
  }
}

Code description:

1. removes the leading 0 from the Num attribute using the regular expression.

2. Gets an array of property names for objects in arr1 by using the Object.keys() method.

3. Traverses the array of attribute names to determine whether it begins with chr_, and if so generates a new attribute name and adds it to the corresponding array object in arr2.