wongjiahau/ttap-web

const sortBy = require("lodash.sortby");
export interface IPartitionable {
  PartitionKey: number;
}

export function Partitionize<T extends IPartitionable>(input: T[]): T[][] {
  return PartitionizeByKey(input, "PartitionKey");
}

export function PartitionizeByKey<T>(input: T[], keyName: string): T[][] {
  if (input.length === 0) {
    return [];
  }
  const result = new Array<T[]>();
  let column = new Array<T>();
  const copy = sortBy(input, [keyName]);
  column.push(copy[0]);
  let currentKey = copy[0][keyName];
  for (let i = 1; i < copy.length; i++) {
    if (copy[i][keyName] === currentKey) {
      column.push(copy[i]);
    } else {
      currentKey = copy[i][keyName];
      result.push(column.slice());
      column = [];
      column.push(copy[i]);
    }
    if (i === copy.length - 1) {
      result.push(column);
    }
  }
  if (result.length === 0) {
    result.push(column);
  }
  return result;
}

export function BinaryPartition<T>(
  input: T[],
  check: (elem: T) => boolean
): [T[], T[]] {
  const right: T[] = [];
  const left: T[] = [];
  for (let i = 0; i < input.length; i++) {
    if (check(input[i])) {
      left.push(input[i]);
    } else {
      right.push(input[i]);
    }
  }
  return [left, right];
}