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Config file

AMA comes with predefined rules and severity for the built-in components and hooks. Those rules have been created to improve the accessibility of those elements and should always be respected.

Customizing log levels can be done via the ama.config.json file to handle edge cases that are out of our control, and require breaking a rule or two.

info

The library does not perform any accessibility checks on the production build!

The log levels​

AMA guidelines are categorised as:

  • MUST and MUST NOT: Those best practices are enforced and AMA overlays an error when fail
  • SHOULD and SHOULD_NOT: Those best practices are preferred and AMA prints only prints a warning message when fail

The possible log levels are:

  • error: The AMA error overlay when a check fails
  • warn: A console.warn is performed when a check fails

AMA Rules​

Log keyGuidelineDefaultCan override
BOTTOM_SHEET_CLOSE_ACTIONMUSTerror
CONTRAST_FAILEDMUSTerror
CONTRAST_FAILED_AAASHOULDwarn
FLATLIST_NO_COUNT_IN_SINGULAR_MESSAGESHOULDwarn
FLATLIST_NO_COUNT_IN_PLURAL_MESSAGEMUSTerror
MINIMUM_SIZEMUSTerror
NO_ACCESSIBILITY_LABEL1MUSTerror
NO_ACCESSIBILITY_ROLE 1MUSTerror
NO_FORM_LABELMUSTerror
NO_FORM_ERRORMUSTerror
NO_KEYBOARD_TRAP 1MUST NOTerror
UPPERCASE_TEXT_NO_ACCESSIBILITY_LABELMUST NOTerror
NO_UPPERCASE_TEXTMUST NOTerror
note

Rules marked with are considered bad practices and cannot be turned off!

Constants​

Elements that perform a contrast check do it on all the children up to the level specified by CONTRAST_CHECKER_MAX_DEPTH.

Constant keyDefault value
CONTRAST_CHECKER_MAX_DEPTH5
{
  "CONTRAST_CHECKER_MAX_DEPTH": 0
}
tip

This can be turned off by specifying a level of 0

accessibilityLabelExceptions​

AMA performs various checks, including one for uppercase. This rule allows specifying a list of approved all-caps accessibility labels.

{
  "accessibilityLabelExceptions": ["FAQ"]
}

Customising the log levels​

Create a JSON file called ama.config.json in the project's root folder to customise the log rules, then specify the custom log level for the wanted key.

Example​

The JSON file does not need to contain all log keys. AMA uses the default rule if a key is not present:

{
  "CONTRAST_FAILED": "warn",
  "CONTRAST_CHECKER_MAX_DEPTH": 0,
  "accessibilityLabelExceptions": ["FAQ"]
}
caution

Whenever the ama.rules.json file is updated, update the copy within the node_modules folder and restart the development server.

cp ama.rules.json node_modules/react-native-ama/

yarn start

Footnotes​

  1. The rule cannot be overridden ↩ ↩2 ↩3