No further changes are expected in the release apart from critical bug fixes.
For faster declaration emits, TypeScript now caches whether internal symbols are accessible in different contexts, along with how specific types are to be printed. This improves general performance in code with fairly complex types.
Other performance enhancements in TypeScript 4.4 promise faster path normalization and path mapping, along with faster incremental builds. An optimization has been added for source map generation of very large output files, and faster
--force builds are offered as well. A
-- force build does not need up-to-date checks to determine which files need to be rebuilt, with project dependencies rebuilt from scratch.
The TypeScript 4.4 release candidate, published August 12, can be accessed through NuGet or via NPM:
npm install typescript@rc
General availability of TypeScript 4.4 is planned for August 24. The beta release was published July 1. Other new capabilities in TypeScript 4.4:
readonlyproperty, or an unmodified parameter, then TypeScript is able to narrow that value appropriately. Different type guard conditions are preserved, not just
symbols and template string patterns now are permitted.
--useUnknownInCatchVariables, changes the default type of
catchclause variables from
unknown. Another new flag,
--exactOptionalPropertyTypes, specifies that optional property types should be interpreted exactly as written.
TypeScript 4.4 follows the May introduction of the production release of TypeScript 4.3. Among other improvements, the TypeScript 4.3 release allowed developers to specify types for reading and writing to properties.