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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-19 00:47:55 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-19 00:47:55 +0000 |
commit | 26a029d407be480d791972afb5975cf62c9360a6 (patch) | |
tree | f435a8308119effd964b339f76abb83a57c29483 /docs/code-quality/lint/linters/eslint-plugin-mozilla/rules/use-isInstance.rst | |
parent | Initial commit. (diff) | |
download | firefox-26a029d407be480d791972afb5975cf62c9360a6.tar.xz firefox-26a029d407be480d791972afb5975cf62c9360a6.zip |
Adding upstream version 124.0.1.upstream/124.0.1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'docs/code-quality/lint/linters/eslint-plugin-mozilla/rules/use-isInstance.rst')
-rw-r--r-- | docs/code-quality/lint/linters/eslint-plugin-mozilla/rules/use-isInstance.rst | 41 |
1 files changed, 41 insertions, 0 deletions
diff --git a/docs/code-quality/lint/linters/eslint-plugin-mozilla/rules/use-isInstance.rst b/docs/code-quality/lint/linters/eslint-plugin-mozilla/rules/use-isInstance.rst new file mode 100644 index 0000000000..7ba4163228 --- /dev/null +++ b/docs/code-quality/lint/linters/eslint-plugin-mozilla/rules/use-isInstance.rst @@ -0,0 +1,41 @@ +use-isInstance +============== + +Prefer ``.isInstance()`` in chrome scripts over the standard ``instanceof`` +operator for DOM interfaces, since the latter will return false when the object +is created from a different context. + +These files are covered: + +- ``*.sys.mjs`` +- ``*.jsm`` +- ``*.xhtml`` with ``there.is.only.xul`` +- ``*.js`` with a heuristic + +Since there is no straightforward way to detect chrome scripts, currently the +linter assumes that any script including the following words are chrome +privileged. This of course may not be sufficient and is open for change: + +- ``ChromeUtils``, but not ``SpecialPowers.ChromeUtils`` +- ``BrowserTestUtils``, ``PlacesUtils`` +- ``document.createXULElement`` +- ``loader.lazyRequireGetter`` +- ``Services.foo``, but not ``SpecialPowers.Services.foo`` + +Examples of incorrect code for this rule: +----------------------------------------- + +.. code-block:: js + + node instanceof Node + text instanceof win.Text + target instanceof this.contentWindow.HTMLAudioElement + +Examples of correct code for this rule: +--------------------------------------- + +.. code-block:: js + + Node.isInstance(node) + win.Text.isInstance(text) + this.contentWindow.HTMLAudioElement.isInstance(target) |