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Sign upfix(compiler-cli): use `null` in type checking of safe navigation operators #37747
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…rators Safe navigation operators in Angular templates will evaluate to `null` if the LHS operand is `null` or `undefined`, however the type checker would use `undefined` instead. This results in inaccurate type checking when `strictNullChecks` is enabled. BREAKING CHANGE: Using the safe navigation operator in templates will now infer the type of the expressions to be a union type including `null`, instead of `undefined` as it previously was. If TypeScript's `strictNullChecks` is enabled together with Angular's `strictTemplates` or `strictSafeNavigationTypes` you may start to see new type errors. The previous behavior of including `undefined` in the type does not correspond with the behavior at runtime, where the `null` value is used instead. Fixes #37622
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Shouldn't TypeScript handle this operator now? As in, shouldn't this have the same semantics as the JS version? |
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JoostK commentedJun 25, 2020
Safe navigation operators in Angular templates will evaluate to
nullif the LHSoperand is
nullorundefined, however the type checker would useundefinedinstead. This results in inaccurate type checking when
strictNullChecksis enabled.BREAKING CHANGE:
Using the safe navigation operator in templates will now infer the type of the
expressions to be a union type including
null, instead ofundefinedas itpreviously was. If TypeScript's
strictNullChecksis enabled together with Angular'sstrictTemplatesorstrictSafeNavigationTypesyou may start to see new type errors.The previous behavior of including
undefinedin the type does not correspond withthe behavior at runtime, where the
nullvalue is used instead.Fixes #37622