一些ts的奇怪用法

enum.ts

//枚举的使用
enum OSName {
  windows,
  darwin,
  linux,
  centos,
  fedora,
  debian,
  ubuntu,
  suse,
  freebsd,
  unknown,
}

interface OS {
  name: OSName;
  version: string;
  arch: string;
}

const os: Array<OS>;

magic.ts

//这样定义一个接口太方便了
interface Map {
  [key: string]: any,
  [index: number]: any,
}

const base = 1024;
const unitSize: Map = {
  P: base ** 5,
  T: base ** 4,
  G: base ** 3,
  M: base ** 2,
  K: base,
  B: 1,
};

//计算字节大小已直观的文本显示
function byteUnit(bytes: number): string {
  bytes = bytes || 0;
  if (bytes === 0) {
    return '0B';
  }

  const keys = Object.keys(unitSize);
  const values = Object.values(unitSize);

  for (let i = 0; i < keys.length; i += 1) {
    const key = keys[i];
    const value = values[i];
    const n = bytes / value;
    const c = Math.floor(n);
    if (c !== 0) {
      return `${Math.round(n)}${key}`;
    }
  }

  return '0B';
}