find total number of elements in between the numbers 0 t0 10, 10 to 20, 20 to 30 and so on in an array. say the array [23,14,67,17,87] so there are 0 numbers from 0 to 10, 2 numbers from 10 to 20, and so on.

CodePudding user response：

This crux of the logic:

const data = [23,14,67,17,87];

console.log(
  data.reduce((results, entry) => {
    // We only are interested in the 10s unit; the 1s don't matter.
    // This discards the 1s unit, and homologates numbers of the same multiple
    // of 10, e.g.
    // 14 → 1
    // 17 → 1
    const factor = Math.floor(entry / 10);
    // Create a human readable key, i.e 10 to 20
    const key = `${factor * 10} to ${(factor * 10)   10}`
    return {
      ...results,
      // If the group has not already been added to the results,
      // this will set the value to 1, otherwise increment by 1.
      [key]: (results[key] ?? 0)   1,
    };
  }, {})
);

You can always sort the groups if needed.