列队 promise及setTimeout

[1, 2, 3, 4, 5].reduce((pre, cur) => {
    setTimeout(() => {
        console.log(cur)
        return
    }, 1000)
})



[1, 2, 3, 4, 5].reduce((pre, cur) => {
        return pre.then(() => {
          return new Promise((resolve, reject) => {
            setTimeout(() => {
              console.log(cur)
              resolve()
            }, 1000)
          })
        })
      }, Promise.resolve())

两个的打印出来 1、2、3、4、5 时间不同

这段代码可以在上个请求执行后 按顺序执行代码 而不会一下子执行全部请求

 

const logger = store => next => action => {
  console.log('dispatching', action)
  let result = next(action)
  console.log('next state', store.getState())
  return result
}




function logger(store) {
  return function wrapDispatchToAddLogging(next) {
    return function dispatchAndLog(action) {
      console.log('dispatching', action)
      let result = next(action)
      console.log('next state', store.getState())
      return result
    }
  }
}

// 相当于科里化