function fMI(num,arr){
    let digit = arr.toString().split('');
    let realDigit = digit.map(Number);
    console.log("Is RealDigit an array: ",Array.isArray(realDigit));
    console.log(realDigit.filter((v,i,a) => (v==num)? i:''));
}

fMI(1,[1, 11, 34, 52, 61]);

// Create a function that takes a number and an array of numbers as a parameter // and returns the indices of the numbers of the array which contain the given number // or returns an empty list (if the number is not part of any of the numbers in the array)

Sample output:
// console.log(findMatchingIndexes(1, [1, 11, 34, 52, 61]));
// should print: [0, 1, 4]

I am struggling to return the indexes of the values from an array.
The code I have written so far takes one number and compares it to the array which the function takes in.
Now, I am at the phase where I want to to return the indexes where the array values equal to the number taken by the function for comparison.

How can I make this work, cause after the filter method, I get only 3 times the number 1, which is not right.

function fMI(num:number,arr:number[]){
       let digit = arr.toString().split('');
       let realDigit = digit.map(Number);
       console.log("Is RealDigit an array: ",Array.isArray(realDigit));
       console.log(realDigit.filter((v,i,a) => (v==num)? i:''));
}

fMI(1,[1, 11, 34, 52, 61]);

>Solution :

New answer

You can use the string method includes like so:

function fMI(num: number, arr: number[]) {
  const indexes: number[] = [];
  arr.forEach((value, index) => {
    if (value.toString().includes(num.toString())) {
      indexes.push(index);
    }
  })
  return indexes;
}

fMI(1, [1, 11, 34, 52, 61]); // [0, 1, 4]

Old answer

You can use forEach with a second argument that is the element index. Note that you are specifying arr as an array of number, so there’s no need to convert them to numbers again.

function fMI(num: number, arr: number[]) {
  const indexes: number[] = [];
  arr.forEach((value, index) => {
    if (value === num) {
      indexes.push(index);
    }
  })
  return indexes;
}

The 4 lines you have written doesn’t help with the logic, that’s why I removed it. If you want to know why, leave a comment on this answer and I will reply your questions.