useful code

[Aaronphy]

check image URL is valid,including base64

async function checkImage(url){
const res = await fetch(url);
const buff = await res.blob();
return buff.type.startsWith('image/');
}

[Aaronphy]

handler factory

import { ipcMain } from 'electron';

class HandlerFactory {
    public static create(scope:string ,bind: any){
      return (name:string, fn:(...args:any[])=>void, includeEvent = false) =>
        ipcMain.handle(`${scope}.${name}`,(...args:any[])=>{
              if(!includeEvent) args = args.slice(1);
              return fn.bind(bind)(...args);
        });
   }
}

[Aaronphy]

background 30s countdown

let st = Date.now(),
    i = 0,
    itv = setInterval(()=>{
        i = ~~((Date.now() - st)/1000);
        if(i >= 3){
            clearInterval(itv)
            alert('time over')
        }
    },1000);

[Aaronphy]

get the ip in nodejs

import { networkInterfaces, NetworkInterfaceInfo } from 'os';

export const getPrivateIPNInfos = (): (NetworkInterfaceInfo | undefined)[] => Object.values(networkInterfaces()) .flatMap(infos => infos?.filter(i => i.family === 'IPv4')) .filter( info => info?.address.match(/(^127.)|(^10.)|(^172.1[6-9].)|(^172.2[0-9].)|(^172.3[0-1].)|(^192.168.)/) !== null );

export const getPrivateIPs = (): (string | undefined)[] => getPrivateIPNInfos().map(i => i?.address);

export const getPrivateExternalIPNInfos = (): (NetworkInterfaceInfo | undefined)[] => Object.values(networkInterfaces()) .flatMap(infos => infos?.filter(i => !i.internal && i.family === 'IPv4')) .filter( info => info?.address.match(/(^10.)|(^172.1[6-9].)|(^172.2[0-9].)|(^172.3[0-1].)|(^192.168.)/) !== null );

export const getPrivateExternalIPs = (): (string | undefined)[] => getPrivateExternalIPNInfos().map(i => i?.address);

[Aaronphy]

retry promise and sleep timer

// 工具函数，用于延迟一段时间
const sleep = (time: number) => {
  return new Promise((resolve) => {
    setTimeout(resolve, time);
  });
};

// 工具函数，用于包裹 try - catch 逻辑
const awaitErrorWrap = async <T, U = any>(
  promise: Promise<T>
): Promise<[U | null, T | null]> => {
  try {
    const data = await promise;
    return [null, data];
  } catch (err: any) {
    return [err, null];
  }
};

// 重试函数
export const retryRequest = async <T>(
  promise: () => Promise<T>,
  retryTimes: number = 3,
  retryInterval: number = 500
) => {
  let output: [any, T | null] = [null, null];

  for (let a = 0; a < retryTimes; a++) {
    output = await awaitErrorWrap(promise());

    if (output[1]) {
      break;
    }

    console.log(`retry ${a + 1} times, error: ${output[0]}`);
    await sleep(retryInterval);
  }

  return output;
};

usage

import { retryRequest } from "xxxx";
import axios from "axios";

const request = (url: string) => { return axios.get(url); };

const [err, data] = await retryRequest(request("https://request_url"), 3, 500);

> method decorator

```typescript
export const retryDecorator = (
  retryTimes: number = 3,
  retryInterval: number = 500
): MethodDecorator => {
  return (_: any, __: string | symbol, descriptor: any) => {
    const fn = descriptor.value;
    descriptor.value = async function (...args: any[]) {
      // 这里的 retryRequest 就是刚才的重试函数
      return retryRequest(fn.apply(this, args), retryTimes, retryInterval);
    };
  };
};

usage

import { retryRequest } from "xxxx";
import axios from "axios";

class RequestClass { @retryDecorator(3, 500) static async getUrl(url: string) { return axios.get(url); } }

const [err, data] = await RequestClass.getUrl("https://request_url");

[Aaronphy]

//版本比较
const isVersionNewerOrEqual = (oldVer, newVer) => {
    try {
        const oldParts = oldVer.split('.');
        const newParts = newVer.split('.');
        for (let i = 0; i < newParts.length; i++) {
            const a = parseInt(newParts[i]);
            const b = parseInt(oldParts[i]);
            if (a > b) return true;
            if (a < b) return false;
        }
        return true;
    } catch (e) {
        return false;
    }
};