how to calculate the total dynamically and store the total number with variable-CodePudding

I have an object which contains the marks of a subject, I am trying to calculate the total of 1st_CQ and 1st_MCQ of the subjects dynamically, after 1st CQ and MCQ I want to calculate the 2nd part 2nd_MCQ & 2nd_CQ, sometimes there will no MCQ like the English subject.

const subNums = {
   english_1st_CQ : 24,
   english_2nd_CQ: 24,
   math_1st_CQ: 40,
   math_1st_MCQ: 10,
   math_2nd_CQ:35,
   math_2nd_MCQ:10,
   // .....
 }

so I have created an Object like this, the idea is to loop the subject and pass the first and second subject numbers into a function and the function will return the total.

    const subject = [
      {
        sub: "english",
        first: {
          CQ1st: "english_1st_CQ",
          MCQ1st: undefined,
        },
        second: {
          CQ1st: "english_2nd_CQ",
          MCQ1st: undefined,
        },
      {
        sub: "math",
        first: {
          CQ1st: "math_1st_CQ",
          MCQ1st: "math_1st_MCQ",
        },
        second: {
          CQ1st: "math_2nd_CQ",
          MCQ1st: "math_2nd_MCQ",
        },
      },
      }]

I am stuck here, I am not able to store the total number inside a variable, [sub.sub] = this throws an error that number 32 is not iterable (cannot read property Symbol(Symbol.iterator)) I want to store the totals with their subject Name like this english: 48, math_1st: 50, math_2nd:45

    const subTotal = subject.map((sub: any) => {
      let obj;
      [sub.sub] = calculateTotal(subNums[sub.first.CQ1st], rest[sub.first.MCQ1st]);
    });

CodePudding user response：

You don't need to create another object to map data. According to your object model, we can find a pattern {subject name}_{subject position}_{suffix} in keys.

With that, we can try to find matched combinations to generate results by reduce

const value = {
   english_1st_CQ: 5,
   english_2nd_CQ: 10,
   math_1st_CQ: 15,
   math_1st_MCQ: 20,
   math_2nd_CQ: 25,
   math_2nd_MCQ: 30,
 };
 
 
 const finalResult = Object.entries(value).reduce((result, [key, value]) => {
    const [subjectName, subjectPosition, suffix] = key.split('_')
    const fullSubjectName = `${subjectName}_${subjectPosition}`
    if(!result[fullSubjectName]) {
      result[fullSubjectName] = 0;
    }
    result[fullSubjectName]  = value
    return result
 }, {})
 
 console.log(finalResult)