Files
Nicholas Carrigan (he/him) 3da4be21bb chore: seed chinese traditional (#42005)
Seeds the chinese traditional files manually so we can deploy to
staging.
2021-05-05 22:43:49 +05:30

2.0 KiB

id, title, challengeType, forumTopicId, dashedName
id title challengeType forumTopicId dashedName
5cdafbe72913098997531682 使用 catch 處理 Promise 失敗的情況 1 301204 handle-a-rejected-promise-with-catch

--description--

當 promise 失敗時會調用 catch 方法。 當 promise 的 reject 方法執行時會直接調用。 用法如下:

myPromise.catch(error => {

});

error 是傳入 reject 方法的參數。

--instructions--

給 promise 添加 catch 方法。 用 error 作爲回調函數的參數,並把 error 打印到控制檯。

--hints--

應該在 promise 上調用 catch 方法。

assert(
  __helpers.removeWhiteSpace(code).match(/(makeServerRequest|\))\.catch\(/g)
);

catch 方法應該有一個回調函數,回調函數參數爲 error

assert(errorIsParameter);

應該打印 error 到控制檯。

assert(
  errorIsParameter &&
    __helpers
      .removeWhiteSpace(code)
      .match(/\.catch\(.*?error.*?console.log\(error\).*?\)/)
);

--seed--

--after-user-code--

const errorIsParameter = /\.catch\((function\(error\){|error|\(error\)=>)/.test(__helpers.removeWhiteSpace(code));

--seed-contents--

const makeServerRequest = new Promise((resolve, reject) => {
  // responseFromServer is set to false to represent an unsuccessful response from a server
  let responseFromServer = false;

  if(responseFromServer) {
    resolve("We got the data");
  } else {  
    reject("Data not received");
  }
});

makeServerRequest.then(result => {
  console.log(result);
});

--solutions--

const makeServerRequest = new Promise((resolve, reject) => {
  // responseFromServer is set to false to represent an unsuccessful response from a server
  let responseFromServer = false;

  if(responseFromServer) {
    resolve("We got the data");
  } else {  
    reject("Data not received");
  }
});

makeServerRequest.then(result => {
  console.log(result);
});

makeServerRequest.catch(error => {
  console.log(error);
});