Skip to content

docs: fix case-sensitivity explanation in highest-available-document-mode #6029

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

Open
wants to merge 2 commits into
base: main
Choose a base branch
from
Open

docs: fix case-sensitivity explanation in highest-available-document-mode #6029

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
d2a0b67
fix: correct case-sensitivity behavior in highest-available-document-…
rajucreate Nov 25, 2025
8be06e0
'
rajucreate Nov 25, 2025
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
19 changes: 16 additions & 3 deletions packages/hint-highest-available-document-mode/README.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -46,10 +46,23 @@ Notes:

## What does the hint check?

By default, the hint checks if the `X-UA-Compatible` response header
is sent with the value of `IE=edge`, and that the `meta` tag isn’t
used.
### Important note about case-sensitivity

The `X-UA-Compatible` header is defined as case-insensitive according to Microsoft's specification.

The hint now correctly performs a **case-insensitive comparison** of the value.
This means the following are all treated as valid:

X-UA-Compatible: IE=edge
X-UA-Compatible: Ie=EdGe
x-ua-compatible: ie=edge

Only values that are not equal to `ie=edge` (ignoring case and spacing)
will trigger an error.

```text
X-UA-Compatible: IE=edge
```
### Examples that **trigger** the hint for defaults

`X-UA-Compatible` response header is not sent:
Expand Down
2 changes: 1 addition & 1 deletion packages/hint-highest-available-document-mode/src/hint.ts
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -80,7 +80,7 @@ export default class HighestAvailableDocumentModeHint implements IHint {
return;
}

if (headerValue !== 'ie=edge') {
if (headerValue?.trim().toLowerCase() !== 'ie=edge') {
context.report(
resource,
getMessage('headerValueShouldBe', context.language),
Expand Down
Loading