# Custom fetch-retry in legacy projects

`fetchRetry.js`
```js
function wait(delay) {
  return new Promise((resolve) => setTimeout(resolve, delay))
}

function fetchRetry({ url, delay = 1000, tries = 0, fetchOptions = {} }) {
  let __triesLeft = tries
  function onError(err) {
    __triesLeft = !!__triesLeft ? __triesLeft - 1 : 0

    if (!__triesLeft) throw err

    return wait(delay).then(() => fetchRetry({ url, delay, tries: __triesLeft, fetchOptions }))
  }
  return fetch(url, fetchOptions).catch(onError)
}
```

### Usage
```js
// --- NOTE: Target action
// 1. Try to use different IPs
const ips = ['178.248.232.203', '2.58.70.214', '159.65.25.117', getAPIBaseUrl()]
const getBaseUrl = ({ ip, url }) => (!validateAnything.hasProtocol(ip) ? `https://${ip}${url}` : `${ip}${url}`)
const getEndpoints = ({ url }) =>
  ips
    .map((ip) => getBaseUrl({ url, ip }))
    .filter((url) => validateAnything.isValidURL(url))
const endpoints = getEndpoints({ url: '/partner_api/tradein/accept' })
const abortController = new AbortController()
const tries = 20

Promise.first(
  endpoints.map((url) =>
    fetchRetry({
      url,
      delay: 30000,
      tries,
      fetchOptions: {
        method: 'POST',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify(data),
        signal: abortController.signal,
      },
    })
  )
)
  .then(async (response) => {
    // QuicklyDone fulfils first

    const res = await response.json()
    if (res.ok) {
      abortController.abort()
      targetAction(res)
    } else throw new Error('/accept response is not ok!')
  })
  .catch((errs) => {
    // Arrary of rejections (if no one resolved)
    // Провалено (ips.length * tries) попыток

    // Or one main Error?
  })
// ---
```

`validateAnything.js`
```js
const validateAnything = {
  hasProtocol(str) {
    const pattern = new RegExp('https?:\\/\\/')
    return !!pattern.test(str)
  },
  hasWWW(str) {
    const pattern = new RegExp(/www./)
    return !!pattern.test(str)
  },
  isValidURL(str) {
    const pattern = new RegExp(/(?:https?):\/\/(\w+:?\w*)?(\S+)(:\d+)?(\/|\/([\w#!:.?+=&%!\-\/]))?/)
    return !!pattern.test(str)
  },
}
```

### Polyfills
```js
if (!Promise.first)
  // https://github.com/huruji/p-first
  Promise.first = function (e) {
    return Promise.all(
      e.map(function (e) {
        return e.then(
          function (e) {
            return Promise.reject(e)
          },
          function (e) {
            return Promise.resolve(e)
          }
        )
      })
    ).then(
      function (e) {
        return Promise.reject(e)
      },
      function (e) {
        return Promise.resolve(e)
      }
    )
  }

if (!Promise.any)
  Promise.any = (o) =>
    new Promise((i, l) => {
      var n, t, v, d, e
      let u = !1,
        c = [],
        h = 0,
        f = []
      function a(o) {
        u || ((u = !0), i(o))
      }
      function r(o) {
        f.push(o), f.length >= h && l(f)
      }
      for (let i of o) h++, c.push(i)
      for (let o of c)
        void 0 !== (null === (n = o) || void 0 === n ? void 0 : n.then) ||
        void 0 !== (null === (t = o) || void 0 === t ? void 0 : t.catch)
          ? (null === (d = null === (v = o) || void 0 === v ? void 0 : v.then((o) => a(o))) ||
              void 0 === d ||
              d.catch((o) => {}),
            null === (e = o) || void 0 === e || e.catch((o) => r(o)))
          : a(o)
    })
```

*See also https://gitlab.com/smartprice/ringeo/-/merge_requests/1818*

#jsVanilla | fetchRetry #smartpriceRINGEO #promise #TCP/IP

```js
// NOTE: Polyfill
if (!Promise.first)
  // https://github.com/huruji/p-first
  Promise.first = function(e){return Promise.all(e.map(function(e){return e.then(function(e){return Promise.reject(e)},function(e){return Promise.resolve(e)})})).then(function(e){return Promise.reject(e)},function(e){return Promise.resolve(e)})};

const SlowlyDone = new Promise((resolve, _reject) => {
  setTimeout(resolve, 10000, "Done slowly");
}); // resolves after 10000ms

const QuicklyDone = new Promise((resolve, _reject) => {
  setTimeout(resolve, 200, "Done quickly");
}); // resolves after 100ms

const Rejection = new Promise((_resolve, reject) => {
  setTimeout(reject, 100, "Rejected"); // always rejected
});

Promise.first([
  SlowlyDone,
  QuicklyDone,
  Rejection,
])
  .then((value) => {
    console.log(value);
    // QuicklyDone fulfils first
  })
  .catch((err) => {
    console.log(err);
    // Arrary of rejections (if no one resolved)
  });

// expected output: Done quickly
```
<Alert type='info' text='ES6 polyfill for `Promise.first` https://github.com/juneidysoo/promise-first/blob/master/index.js' header='See also' />

Promise.first  #polyfill #jsVanilla

```js
// NOTE: The method Promise.any was supported in node.js 15.0.0
// If your node.js version is old, so you could update it and try again
// ...or use polyfill:
if (!Promise.any)
  Promise.any=o=>new Promise(((i,l)=>{var n,t,v,d,e;let u=!1,c=[],h=0,f=[];function a(o){u||(u=!0,i(o))}function r(o){f.push(o),f.length>=h&&l(f)}for(let i of o)h++,c.push(i);for(let o of c)void 0!==(null===(n=o)||void 0===n?void 0:n.then)||void 0!==(null===(t=o)||void 0===t?void 0:t.catch)?(null===(d=null===(v=o)||void 0===v?void 0:v.then((o=>a(o))))||void 0===d||d.catch((o=>{})),null===(e=o)||void 0===e||e.catch((o=>r(o)))):a(o)}));

const SlowlyDone = new Promise((resolve, _reject) => {
  setTimeout(resolve, 500, "Done slowly");
}); // resolves after 500ms

const QuicklyDone = new Promise((resolve, _reject) => {
  setTimeout(resolve, 200, "Done quickly");
}); // resolves after 100ms

const Rejection = new Promise((_resolve, reject) => {
  setTimeout(reject, 100, "Rejected"); // always rejected
});

Promise.any([
  SlowlyDone,
  QuicklyDone,
  Rejection,
])
  .then((value) => {
    console.log(value);
    // QuicklyDone fulfils first
  })
  .catch((err) => {
    console.log(err);
    // Arrary of rejections (if no one resolved)
  });

// expected output: Done quickly
```

Promise.any #polyfill  #jsVanilla

https://github.com/nolanlawson/promise-worker

https://bl.ocks.org/nolanlawson/05e74a8408a099635c9a38f839b5ae9f

PromiseWorker WebWorker example

https://stackoverflow.com/a/61225235

The problem is very likely the content of one your variables ($user, $path, $file, $line) inside your message, which creates an invalid markdown string. Maybe you have an opening markdown symbol without the corresponding closing one. Like `*` or `_`.

If this doesn't help, please post here the exact message, with variables replaced, so we can spot markdown errors.

#telegramBot UnhandledPromiseRejectionWarning: Error: 400: Bad Request: can't parse entities: Can't find end of the entity starting at byte offset 113

*Есть лучший вариант для записи такой последовательности?*

```js
fn1.then(() => {
  fn2.then(() => {
    fn3.finally(() => {
      // Some code...
    })
  })
})
```

> да, вкладывать промисы никогда не надо
> из then `fn1.then` возвращаете `fn2`
> и строите плоскую цепочку промисов

```js
fn1
  .then(() => fn2)
  .then(() => fn3)
  .finally(() => {
    // Some code...
  })
```

promise

#jsVanilla | fetchRetry #smartpriceRINGEO #promise #TCP/IP

Promise.first #polyfill #jsVanilla

Promise.any #polyfill #jsVanilla

PromiseWorker WebWorker example

#telegramBot UnhandledPromiseRejectionWarning: Error: 400: Bad Request: can't parse entities: Can't find end of the entity starting at byte offset 113

#jsVanilla #promise | Promise hell