PctRankArray.ts

function pctRankArray(array:number[]){
    const normalMap = [...new Set(array)]
        .sort((x, y) => x - y)
        .reduce((map, val, ix, arr) => {
          map.set(val, ix / (arr.length - 1));
          return map;
        }, new Map<number, number>());
    return array.map(v => normalMap.get(v))
}