promise-fault-tolerant-race.js

let promises = []

promises[0] = new Promise((resolve, reject) => {
    setTimeout(() => {
        console.log("first promise")
        reject("first promise")
    }, 1000)
})

promises[1] = new Promise((resolve, reject) => {
    setTimeout(() => {
        console.log("second promise")
        resolve("second promise")
    }, 2000)
})

promises[2] = new Promise((resolve, reject) => {
    setTimeout(() => {
        console.log("third promise")
        resolve("third promise")
    }, 3000)
})

function safeRace(promises, errorHandler = (_ => _)) {
    return new Promise((resolve, _) => {
        for (const promise of promises) {
            promise
            .then(value => {
                resolve(value)
            })
            .catch(errorHandler)
        }
    })
}


safeRace(promises).then(value => {
    console.log('winner: ' + value)
})