To write (4 - 1) instead of just 3 in the code: is it something people even do?

[admit8490]

In the code below, I wrote (4 - 1) instead of just 3.

It looks kind of dumb, but I see logic in this type of decisions, it described in the comments. Don’t know: people do stuff like that or not?

Let me know, if link to the challenge is required, my question above is not about ‘how to solve this’, so I didn’t post the link right away.

function largestGridProduct(arr) {

    let size = arr.length;
    let maxProduct = 0;

    for (let i = 0; i < size; i++) {
  
        for (let j = 0; j < size; j++) {
          
          //to check all horizontal products
          if (j <= size - 4) {
            
            let testProduct = arr[i][j];
            for (let n = 1; n < 4; n++) {
                testProduct *= arr[i][j + n];
            }
            if (testProduct > maxProduct) {maxProduct = testProduct;}

            
            //nest another if block >>> also can check L to R diagonal products
            if (i <= size - 4) {
              
              let testProduct = arr[i][j];
              for (let n = 1; n < 4; n++) {
                testProduct *= arr[i + n][j + n];
              }
              if (testProduct > maxProduct) {maxProduct = testProduct;}
            }
          }

          //to check all vertical and R to L diagonal products
          //use symmetric if logic

          if (i <= size - 4) {

            let testProduct = arr[i][j];
            for (let n = 1; n < 4; n++) {
                testProduct *= arr[i + n][j];
            }
            if (testProduct > maxProduct) {maxProduct = testProduct;}

            //in the below (4 - 1) expression used instead of (3) intentionally:
            //all occurances of 4 in this code can be replaced with parameter
            //if function will be modified to:
            //find largest product of n adjacent numbers in NxN grid

            if (j >= 4 - 1) {

                let testProduct = arr[i][j];
                for (let n = 1; n < 4; n++) {
                    testProduct *= arr[i + n][j - n];
                }
                if (testProduct > maxProduct) {maxProduct = testProduct;}
            }
          }

        }
        
      }

    return maxProduct;
  }

[JeremyLT]

Hard-coded ‘magic numbers’, no matter how you write them, are usually considered a bad idea.