# definedundefined - use `angular.isDefined` and `angular.isUndefined` instead of other undefined checks You should use the angular.isUndefined or angular.isDefined methods instead of using the keyword undefined. We also check the use of !angular.isUndefined and !angular.isDefined (should prefer the reverse function) ## Examples The following patterns are considered problems; /*eslint angular/definedundefined: 2*/ // invalid value === undefined // error: You should not use directly the "undefined" keyword. Prefer angular.isUndefined or angular.isDefined // invalid value !== undefined // error: You should not use directly the "undefined" keyword. Prefer angular.isUndefined or angular.isDefined // invalid !angular.isUndefined(value) // error: Instead of !angular.isUndefined, you can use the out-of-box angular.isDefined method // invalid !angular.isDefined(value) // error: Instead of !angular.isDefined, you can use the out-of-box angular.isUndefined method The following patterns are **not** considered problems; /*eslint angular/definedundefined: 2*/ // valid angular.isUndefined(value) // valid angular.isDefined(value) ## Version This rule was introduced in eslint-plugin-angular 0.1.0 ## Links * [Rule source](../rules/definedundefined.js) * [Example source](../examples/definedundefined.js)