class SuperTask {
constructor(parallelCount = 2) {
this.parallelCount = parallelCount
this.tasks = []
this.ruuingCount = 1
}
add(task1) {
return new Promise((resolve, reject) => {
this.tasks.push({
task1,
resolve,
reject
})
this._run()
})
}
_run() {
while ((this.ruuingCount < this.parallelCount) && this.tasks.length) {
let { task1, resolve, reject } = this.tasks.shift()
this.ruuingCount++
Promise.resolve(task1()).then(resolve, reject).finally(() => {
this.ruuingCount--;
this._run()
}
)
}
}
}
function timeout(time) {
return new Promise((resolve) => {
setTimeout(() => {
resolve()
}, time)
})
}
const superTask = new SuperTask()
function addTask(time, name) {
superTask.add(() => timeout(time)).then(() => {
console.log('task ' + name + ' finish')
})
}
addTask(1000, 1)
addTask(1000, 2)
addTask(1000, 3)
addTask(1000, 4)
