❝
When writing a Node service, you may encounter the occasional request failure when calling a third-party interface. Implement a retry mechanism to increase the success rate.
❞
implementation
const isFunction = function(arg) {
return toString.call(arg) === '[object Function]';
};
Promise.retry = (fn, options = {}) = > {
if(! isFunction(fn))throw new Error('fn is not a function')
const { max = 3, delay = 0 } = options
let curMax = max
const delayExec = (a)= > delay && new Promise(resolve= > setTimeout(resolve, delay))
return new Promise(async (resolve, reject) => {
while (curMax > 0) {
try {
const res = await fn()
resolve(res)
return
} catch (error) {
await delayExec()
curMax--
console.warn('residual number${curMax}`)
if(! curMax) reject(error)
}
}
})
}
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const resolveData = (a)= > {
return new Promise((resolve, reject) = > {
setTimeout(
(a)= > (Math.random() > 0.5 ? resolve('success') : reject(new Error('failure')))
, 1000.
)
})
}
;(async () = > {
try {
const res = await Promise.retry(resolveData, { delay: 1000 })
console.warn('result', res)
} catch (error) {
console.warn(error)
}
}) ()
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