Skip to content

Detect if access to localStorage is forbidden by the user's browser #55080

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 3 commits into from
Oct 18, 2018
Merged

Detect if access to localStorage is forbidden by the user's browser #55080

Changes from all commits
Commits
Show all changes
3 commits
Select commit Hold shift + click to select a range
d4e2dca
Detect if access to localStorage is forbidden by the user's browser
thanatos Oct 15, 2018
8362aa2
Extract localStorage tests out into a helper method; use in getCurren…
thanatos Oct 16, 2018
cbe98ec
Move usableLocalStorage() above functions that make use of it
thanatos Oct 17, 2018
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
22 changes: 20 additions & 2 deletions src/librustdoc/html/static/storage.js
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -26,16 +26,34 @@ function onEach(arr, func) {
return false;
}

function usableLocalStorage() {
Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Can move this function above the two others please? It's just me being careful but better be safe than sorry. :)

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Done.

The order shouldn't matter; in JS, function declarations are "hoisted" to the top of the file (in the case that they're at the top-level, and not contained in another function), so they appear to happen prior to code actually running. (Function expressions are not, and the MDN article notes that.)

Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Try this code then:

foo();

function foo() {
    console.log('hello');
}

// Check if the browser supports localStorage at all:
if (typeof(Storage) === "undefined") {
return false;
}
// Check if we can access it; this access will fail if the browser
// preferences deny access to localStorage, e.g., to prevent storage of
// "cookies" (or cookie-likes, as is the case here).
try {
window.localStorage;
} catch(err) {
// Storage is supported, but browser preferences deny access to it.
return false;
}

return true;
}

function updateLocalStorage(name, value) {
if (typeof(Storage) !== "undefined") {
if (usableLocalStorage()) {
localStorage[name] = value;
} else {
// No Web Storage support so we do nothing
}
}

function getCurrentValue(name) {
if (typeof(Storage) !== "undefined" && localStorage[name] !== undefined) {
if (usableLocalStorage() && localStorage[name] !== undefined) {
return localStorage[name];
}
return null;
Expand Down