I want to reduce duplication in my JavaScript syntax.

No matter how much I think about it, it doesn't come to mind.

It doesn't matter if it is for loop or any syntax!

i add some of case and result

if if it is correct answer would be result

    //   case 1

  //  const max = [1, 31, 0, 0]

  //  const min = [1, 31];
  
  //  result = [3, 5]

  //   case 2

  // const max = [0, 0, 0, 0, 0, 0]

  // const min = [0, 0]

  //  result = [1, 6]

  //   case 3

  // const max = [45, 4, 35, 20, 3, 9]

  // const min = [45, 4, 35, 20, 3, 9]
  
  //  result = [1, 1]

    if (max.length === 6) {
      answer[0] = 1;
    } else if (max.length === 5) {
      answer[0] = 2;
    } else if (max.length === 4) {
      answer[0] = 3;
    } else if (max.length === 3) {
      answer[0] = 4;
    } else if (max.length === 2) {
      answer[0] = 5;
    } else {
      answer[0] = 6;
    }

    if (min.length === 6) {
      answer[1] = 1;
    } else if (min.length === 5) {
      answer[1] = 2;
    } else if (min.length === 4) {
      answer[1] = 3;
    } else if (min.length === 3) {
      answer[1] = 4;
    } else if (min.length === 2) {
      answer[1] = 5;
    } else {
      answer[1] = 6;
    }

CodePudding user response：

is max and min length between 1 and 6? because judging your code, it looks like it.

answer[0] = 7 - max.length

sure looks a bit neater? at the least you could eliminate many if blocks and leave the else block in case max.length is not an integer between 1 and 6

//pseudocode
if( max.length between 1 and 6 inclusive) {
    answer[0] = 7- max.length
} else { 
    answer[0] = some default value, 6? 
}

the 7 looks like a magic number, but with more context, you can name it something better

CodePudding user response：

const getAnswers = x => (x < 1 || x > 6) ? 6 : 7 - x;

//   case 1
let max = [1, 31, 0, 0]
let min = [1, 31];
//  result = [3, 5]
let answer = [getAnswers(max.length), getAnswers(min.length)];
console.log('max.length: ', max.length, ' min.length: ', min.length, ' answer array: ', answer);

//   case 2
max = [0, 0, 0, 0, 0, 0]
min = [0]
//  result = [1, 6]
answer = [getAnswers(max.length), getAnswers(min.length)];
console.log('max.length: ', max.length, ' min.length: ', min.length, ' answer array: ', answer);

//   case 3
max = [45, 4, 35, 20, 3, 9]
min = [45, 4, 35, 20, 3, 9]
//  result = [1, 1]
answer = [getAnswers(max.length), getAnswers(min.length)];
console.log('max.length: ', max.length, ' min.length: ', min.length, ' answer array: ', answer);

CodePudding user response：

By reducing duplication, do you mean you want to decrease the length of your code or increase readability?

If you want to increase readability, some people prefer select/case than if/elseif:

switch(max.length) {
  case 6:
    answer[0] = 1;
    break;
  case 5:
    answer[0] = 2;
    break;
  case 4:
    answer[0] = 3;
    break;
  case 3:
    answer[0] = 4;
    break;
  case 2:
    answer[0] = 5;
    break;
  default:
    answer[0] = 6;
}

If you want to reduce length, you can just do something like @Bergi said in comment:

answer = [7-max.length, 7-min.length];

But if max and min variable is from user input or from external source, unexpected thing may occurs:

max = {length: -5};
min = {length: -99};
answer = [7-max.length, 7-min.length];
console.log(answer)
// outputs [12,106]

The code may outputs a number outside 1-6 integer range.

So you should also add some Math.max and Math.min if you want your code to behave exactly like your if-elseif statement:

max = {length: -5};
min = {length: -99};
answer = [
  Math.max(Math.min(7-max.length,1),6),
  Math.max(Math.min(7-min.length,1),6)
 ];
console.log(answer)
// outputs [6,6]

Of course if you take input from external source you should sanitize/validate it first, but if it's an overkill, you can also use the above Math.min and Math.max function

CodePudding user response：

you need to write just these two lines instead :)

answer[0] = 7 - max.length
answer[1] = 7 - min.length