使用async / await是從Promise.reject（）接收已解決的Promise的唯一方法嗎？

Question

我下面有以下代碼。 我想做的是分別處理網絡錯誤情況和返回的HTTP服務器錯誤情況。

fetch("$imageUploadUrl", {
          method: "POST",
          mode: "same-origin",
          cache: "no-store",
          credentials: "same-origin",
          redirect: "error",
          referrer: "origin",
          body: formData
      }).catch(function(error) {
        failure("There was an error while uploading the image");
      }).then(function(response) {
          if (response.ok){
            return Promise.resolve(response.json());
        } else {
            return Promise.reject(response.text())
        }
      }).then(function(result) {
        success(result.location);
      }).catch(function(errorText) {
          return failure (errorText);
      })

但是，與Promise.resolve()不同， Promise.reject() response.text()在返回前不等待從response.text()解析承諾。 我設法通過添加async / await來收到已解決的諾言：

fetch("$imageUploadUrl", {
          method: "POST",
          mode: "same-origin",
          cache: "no-store",
          credentials: "same-origin",
          redirect: "error",
          referrer: "origin",
          body: formData
      }).catch(function(error) {
        failure("There was an error while uploading the image");
      }).then(async function(response) {
          if (response.ok){
            return Promise.resolve(response.json());
        } else {
            return Promise.reject(await response.text())
        }
      }).then(function(result) {
        success(result.location);
      }).catch(function(errorText) {
          failure(errorText);
      });

這是達到我目標的唯一方法嗎？

我也嘗試這樣做：

fetch("$imageUploadUrl", {
          method: "POST",
          mode: "same-origin",
          cache: "no-store",
          credentials: "same-origin",
          redirect: "error",
          referrer: "origin",
          body: formData
      }).catch(function(error) {
        failure("There was an error while uploading the image");
      }).then(function(response) {
          if (response.ok){
            return Promise.resolve(response.json());
        } else {
            return Promise.reject(response.text())
        }
      }).then(function(result) {
        success(result.location);
      }).catch(function(textPromise) {
          return textPromise;
      }).then(function(text) {
        console.log(text);
      })

但是，即使我在上面的代碼中調用Promise.resolve()時，也總是調用console.log的最后一個，因為它附加在fetch函數本身的promise上。 你知道為什么會這樣嗎？

Answer 1

您可以等待諾言，然后拒絕它：

return response.text().then(text => Promise.reject(text));

Answer 2

那這個版本呢：

const options = {
  method: 'POST',
  mode: 'same-origin',
  cache: 'no-store',
  credentials: 'same-origin',
  referrer: 'origin',
  body: formData
}

async function parseResponse (response) {
  try {
    success(await response.json())
  } catch () {
    failure(await response.text())
  }
}

function parseError (err) {
  failure(`Error uploading file: ${err}`)
}

fetch('$imageUploadUrl', options)
  .then(parseResponse)
  .catch(parseError)