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-rw-r--r-- | docs/code-quality/lint/linters/eslint-plugin-mozilla/rules/reject-import-system-module-from-non-system.rst | 36 |
1 files changed, 36 insertions, 0 deletions
diff --git a/docs/code-quality/lint/linters/eslint-plugin-mozilla/rules/reject-import-system-module-from-non-system.rst b/docs/code-quality/lint/linters/eslint-plugin-mozilla/rules/reject-import-system-module-from-non-system.rst new file mode 100644 index 0000000000..d168676745 --- /dev/null +++ b/docs/code-quality/lint/linters/eslint-plugin-mozilla/rules/reject-import-system-module-from-non-system.rst @@ -0,0 +1,36 @@ +reject-import-system-module-from-non-system +=========================================== + +Rejects static import declaration for system modules (``.sys.mjs``) from non-system +modules. + +Using static import for a system module into a non-system module would create a separate instance of the imported object(s) that is not shared with the other system modules and would break the per-process singleton expectation. + +The reason for this is that inside system modules, a static import will load the module into the shared global. Inside non-system modules, the static import will load into a different global (e.g. window). This will cause the module to be loaded into different scopes, and hence create separate instances. The fix is to use ``ChromeUtils.importESModule`` which will import the object via the system module shared global scope. + + +Examples of incorrect code for this rule: +----------------------------------------- + +Inside a non-system module: + +.. code-block:: js + + import { AppConstants } from "resource://gre/modules/AppConstants.sys.mjs"; + +Examples of correct code for this rule: +--------------------------------------- + +Inside a non-system module: + +.. code-block:: js + + const { AppConstants } = ChromeUtils.importESModule( + "resource://gre/modules/AppConstants.sys.mjs" + ); + +Inside a system module: + +.. code-block:: js + + import { AppConstants } from "resource://gre/modules/AppConstants.sys.mjs"; |