Find peaks including plateaus in a 1D array

findPeaks.js

const findPeaks = arr => arr.reduce((result, curr, i) => {
  const prev = arr[i - 1];
  const next = arr.slice(i).find(item => item !== curr);

  if(curr > prev && curr > next) {
    result.pos.push(i);
    result.peaks.push(curr);
  }

  return result;
}, {
  pos:[],
  peaks:[],
});