Understanding of the Promise.prototype.finally () of

Promise.prototype.finally()

Promise.prototype.finally() Method, regardless of success or failure will be executed on a promise, and the resolution will be passed through on a promise of the case, carefully understand the following example default:

var p = Promise.resolve('ok')
  .finally(() => { 
    return Promise.reject('这里只有返回被拒绝的 promise 或者 throw 一个错误，才会影响当前 finally 返回的新 promise 的决议') })
  .then(value => {
    console.log('成功', value)
  }, (err) => {
    console.log('失败', err)
  });

Summary:
limited impact on the promise their resolution finally returned, it can be changed to resolve on a reject, it can be changed to another on a reject reject, but can not put on a reject changed to resolve.

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参考：
MDN Promise.prototype.finally()