This value is used to report an error message from an asynchronous API, when the asynchronous API is given a callback. This is useful for extensions that are using the callback-based version of the WebExtension APIs.
You don't need to check this property if you are using the promise-based version of the APIs: instead, pass an error handler to the promise:
const gettingCookies = browser.cookies.getAll();
gettingCookies.then(onGot, onError);
runtime.lastError
property is set when an asynchronous function has an error condition that it needs to report to its caller.
If you call an asynchronous function that may set
lastError
, you are expected to check for the error when you handle the result of the function. If
lastError
has been set and you don't check it within the callback function, then an error will be raised.
let myError = browser.runtime.lastError; // null or Error object
An
Error
object representing the error. The
message
特性为
string
with a human-readable description of the error . If
lastError
has not been set, the value is
null
.
Set a cookie, using a callback to log the new cookie or report an error:
function logCookie(c) {
if (browser.runtime.lastError) {
console.error(browser.runtime.lastError);
} else {
console.log(c);
}
}
browser.cookies.set(
{url: "https://developer.mozilla.org/"},
logCookie
);
The same, but using a promise to handle the result of
setCookie()
:
function logCookie(c) {
console.log(c);
}
function logError(e) {
console.error(e);
}
const setCookie = browser.cookies.set(
{url: "https://developer.mozilla.org/"}
);
setCookie.then(logCookie, logError);
注意：
runtime.lastError
是别名化的
extension.lastError
. They are set together, and checking either one will work.
BCD tables only load in the browser
注意：
This API is based on Chromium's
chrome.runtime
API. This documentation is derived from
runtime.json
in the Chromium code.
Microsoft Edge compatibility data is supplied by Microsoft Corporation and is included here under the Creative Commons Attribution 3.0 United States License.
最后修改： , 由 MDN 贡献者