# What changed in flow-bin > 120 changes in flow-bin 0.335 to 0.337 from its official release notes, upgrade guides and advisories: 37 breaking, 1 deprecations, 24 new APIs and options. Each one cited. Sources checked 2026-10-28. HTML: https://unstale.sh/npm/flow-bin/ To see which of these apply to a repository, run `npx @unstale/cli init` in it. ## flow-bin 0.337 ### Breaking changes - Function and Object now represent their prototypes rather than any; code relying on their former any behavior may get new errors. (0.337.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.337.0) - Uses TypeScript's CallableFunction.bind overloads, reporting bound-argument errors at bind and representing remaining parameters as a tuple; bound methods use these overloads too. (0.337.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.337.0) - Supports readonly T[] in unlabeled tuple elements and requires parentheses when optional. (0.337.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.337.0) - ESTree output emits the bound as a bare type node or null; Babel output keeps the TypeAnnotation wrapper, and the TypeScript-to-Flow API translator generates extends bounds. (0.337.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.337.0) ### New APIs and options - Flow supports assertion functions; give invariant an asserts signature if relying on Flow's special handling of it. (0.337.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.337.0) - ESTree enum declarations use a unified EnumBody node with string-or-null explicitType; Babel output retains its existing enum body types. (0.337.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.337.0) - Its options parameter now takes Intl.NumberFormatOptions. (0.337.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.337.0) - Executes runtime Flow syntax in CommonJS and ES modules while preserving original stack locations. (0.337.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.337.0) - Adds formatRange, formatRangeToParts, and ES2023 NumberFormat options; format accepts bigint and numeric strings. (0.337.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.337.0) - Adds library definitions for Intl.Segmenter and Intl.supportedValuesOf. (0.337.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.337.0) ### Behavior and default changes - Assertion narrowing now works through this and super, including receiver assertions. (0.337.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.337.0) - Readonly now supports Array and ReadonlyArray types. (0.337.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.337.0) ### Tooling - Adds ES2024 ArrayBuffer resizing, transfer, and constructor options to the library definitions. (0.337.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.337.0) ### Fixes and other changes - Prevents unsound assertion narrowing when annotations refer to shadowed local declarations. (0.337.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.337.0) - Reuses TypeScript declarations while preserving Flow covariance and callback compatibility. (0.337.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.337.0) - Adds missing AST fields and node types; implicitDeclare is omitted unless true. (0.337.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.337.0) - TypeScript definitions now parse namespace export aliases and ambient exported members. (0.337.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.337.0) - Preserves nominal opaque inference when checking nullable targets. (0.337.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.337.0) - Opaque upper bounds are now honored in template interpolation and nullable subtyping. (0.337.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.337.0) - Optional class method signatures are now parsed in JavaScript and TypeScript files. (0.337.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.337.0) - Aligns Proxy APIs with TypeScript and checks array elements against numeric interface indexers. (0.337.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.337.0) - Qualified type references through a union of namespaces now look up the type in each namespace. (0.337.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.337.0) - Avoids spurious recursion-limit errors for conditions, match, and other expressions involving trivially recursive generic type aliases. (0.337.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.337.0) - Aligns Reflect APIs with TypeScript property, descriptor, key, and constructor definitions. (0.337.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.337.0) - localeCompare, toLocaleLowerCase, and toLocaleUpperCase accept Intl.LocalesArgument; matchAll with a RegExp returns RegExpExecArray matches. (0.337.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.337.0) - Optional TypeScript constructor parameter properties are now parsed. (0.337.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.337.0) - The parser now accepts destructured parameters outside declaration files. (0.337.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.337.0) - The parser now accepts typed function overload signatures in TypeScript implementation files. (0.337.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.337.0) ## flow-bin 0.336 ### Breaking changes - Calls can infer narrower literal types, so explicit annotations may be needed where broader types are required. (0.336.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.336.0) - Unconstrained class type arguments now use their bounds instead of `empty`. (0.336.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.336.0) - The command now uses Flow parser packages and requires Node 18 and Prettier 3. (0.336.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.336.0) - Inference can expose previously hidden parameter-type errors, including functions that do not satisfy an inferred rest-parameter type. (0.336.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.336.0) - The global type is now `Intl.LocalesArgument`; library declarations such as flow-typed's `declare var Intl` must be removed because they hide the builtin namespace. (0.336.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.336.0) - Removed; use `React.ComponentProps` instead. (0.336.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.336.0) - Flow checks ref compatibility for JSX tags typed as `string`, exposing refs that assume a more specific element type. (0.336.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.336.0) - Rest destructuring of exact tuples now excludes preceding elements' types from the rest value. (0.336.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.336.0) - Variance annotations are now checked through tuple type spreads. (0.336.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.336.0) ### New APIs and options - Added to the library definitions. (0.336.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.336.0) - Added to the library definitions. (0.336.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.336.0) - Bigint Atomics support and `Atomics.pause` are added to the library definitions. (0.336.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.336.0) - Additional Date constructor signatures are added. (0.336.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.336.0) - Decorator context and metadata types are now available. (0.336.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.336.0) - Added to the library definitions. (0.336.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.336.0) - Added to the library definitions. (0.336.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.336.0) - The library definitions add `Error.isError`. (0.336.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.336.0) - `Function` now includes `[Symbol.metadata]`. (0.336.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.336.0) - The type now includes `'unknown'`. (0.336.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.336.0) - The library definitions add `Promise.try`. (0.336.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.336.0) - RegExp indices and flags are added to the library definitions. (0.336.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.336.0) - Added to the library definitions. (0.336.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.336.0) - Tuple types can have trailing rest elements, and array literals ending in array spreads and rest-parameter arguments can flow to these types. (0.336.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.336.0) - Typed arrays gain `findLast`, `findLastIndex`, `toReversed`, `toSorted`, and `with`; their constructors can be called without arguments. Find callbacks have updated narrowing and `this` annotation behavior. (0.336.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.336.0) - Well-formed string methods are added to the library definitions. (0.336.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.336.0) ### Behavior and default changes - Functions and constructors are now accepted as builtin `Function` values. (0.336.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.336.0) - Explicit `this` parameters on methods in library definitions no longer need to accept the instance type. (0.336.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.336.0) - Returns inside functions nested in a type guard function are no longer checked against the enclosing type guard. (0.336.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.336.0) ### Tooling - TypeScript signatures for `Array.fromAsync` are added. (0.336.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.336.0) - Intl is now a builtin namespace with TypeScript-compatible definitions through ES2020, including locale, formatting, and canonicalization APIs. (0.336.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.336.0) ### Fixes and other changes - The property is now typed `any[]`, matching TypeScript. (0.336.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.336.0) - Additional ArrayBuffer constructor signatures are added. (0.336.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.336.0) - It now extends `AsyncIteratorObject` and includes `[Symbol.asyncDispose]`. (0.336.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.336.0) - Decorator definitions now match TypeScript, and `ClassDecorator` accepts classes. (0.336.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.336.0) - Declaration merging for `declare class` now preserves variance annotations. (0.336.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.336.0) - References inside namespace blocks now see members merged across blocks and library files. (0.336.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.336.0) - Its declarations now match TypeScript, including `from` overloads, readonly size properties, boolean-returning `find` predicates, and callbacks that cannot annotate `this`. (0.336.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.336.0) - Hover links no longer include the hovered declaration itself. (0.336.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.336.0) - Declaration merging for interfaces now preserves variance annotations. (0.336.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.336.0) - The legacy options alias now matches TypeScript. (0.336.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.336.0) - The legacy options alias now matches TypeScript. (0.336.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.336.0) - The legacy options alias now matches TypeScript. (0.336.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.336.0) - Parser source columns are now correct after characters represented by surrogate pairs. (0.336.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.336.0) - Functions and constructors are now accepted as builtin `Object` values. (0.336.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.336.0) - Fixed spurious indexed-access errors involving recursive class type-argument bounds. (0.336.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.336.0) - Type arguments used in later tuple spreads are now inferred instead of left underconstrained. (0.336.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.336.0) ## flow-bin 0.335 ### Breaking changes - The legacy builtin_lib=flowlib option is removed. (0.335.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.335.0) - The legacy builtin_lib=flowlib-with-lib-dom-d-ts option is removed. (0.335.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.335.0) - Deprecated syntax now consistently causes errors, including in library definition files. (0.335.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.335.0) - This Flow config option is removed. (0.335.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.335.0) - This Flow config option is removed. (0.335.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.335.0) - This Flow config option is removed. (0.335.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.335.0) - This Flow config option is removed. (0.335.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.335.0) - This Flow config option is removed. (0.335.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.335.0) - This Flow config option is removed. (0.335.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.335.0) - This Flow config option is removed. (0.335.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.335.0) - Some JSX expressions previously considered underconstrained now infer unknown. (0.335.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.335.0) - Map.groupBy type parameters are now ordered , matching TypeScript. (0.335.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.335.0) - Type arguments flowing from a polymorphic value to a non-polymorphic type are now solved, potentially surfacing previously hidden errors. (0.335.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.335.0) - Promise now uses TypeScript-style instance and constructor interfaces, which may change errors for code relying on its previous class typing. (0.335.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.335.0) - React.PropsOf now uses React.ComponentProps to find component props; additional errors may occur. (0.335.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.335.0) - Constructing a $ReadOnlyArray now causes an error. (0.335.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.335.0) - dotAll is now read-only, matching TypeScript. (0.335.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.335.0) - This Flow config option is removed. (0.335.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.335.0) - This Flow config option is removed. (0.335.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.335.0) - This Flow config option is removed. (0.335.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.335.0) - replaceAll has separate overloads for replacement strings and replacer functions; passing a union of those types is an error. (0.335.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.335.0) - Symbol now uses TypeScript-style instance and constructor interfaces, which may change errors for code relying on its previous class typing. (0.335.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.335.0) - Symbol() now only accepts a string or number description. (0.335.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.335.0) - Fixed inference that incorrectly used a bound or unknown; more underconstrained errors may appear. (0.335.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.335.0) ### Deprecations - React.ElementConfig is deprecated; use React.ComponentProps instead. It will be removed in the next version. (0.335.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.335.0) ### New APIs and options - Promise.withResolvers is added to the library definitions. (0.335.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.335.0) - The undefined type can now be used in library definitions, where it means void. (0.335.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.335.0) ### Behavior and default changes - Applying as const to template literals now infers template literal types like TypeScript. (0.335.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.335.0) - User-defined assertion conditions now check member access in test context. (0.335.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.335.0) - Arguments to new X(...) are contextually typed when X is annotated with the typeof of a constructor interface value. (0.335.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.335.0) - Implicit instantiation can infer a type argument through React.ComponentProps and other conditional types with infer. (0.335.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.335.0) - Template literals infer precise types in const declarations and annotated initializers. (0.335.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.335.0) - typeof x === 'function' now refines builtin constructors and interfaces with call signatures as functions. (0.335.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.335.0) ### Tooling - flow-remove-types supports abstract classes and members, override modifiers, satisfies, optional class fields, and additional type-only imports and exports. (0.335.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.335.0) - The unnecessary-invariant lint is renamed to unnecessary-assertion; the old name remains accepted. (0.335.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.335.0) ### Fixes and other changes - Assertion functions are supported when exported through CommonJS, in return position, and in arrow expression bodies. (0.335.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.335.0) - ESM default imports of CommonJS assertion functions and callable objects with asserts call signatures are recognized. (0.335.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.335.0) - Extends now uses the prototype of a constructor interface without a construct signature instead of reporting not inheritable. (0.335.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.335.0) - Exported declare classes extending builtins now inherit the builtin's statics and constructor. (0.335.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.335.0) - instanceof now uses the prototype of a constructor interface without a construct signature instead of narrowing to empty. (0.335.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.335.0) - React.ComponentProps<'div'> now includes the optional ref prop. (0.335.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.335.0) - RegExp.prototype[Symbol.matchAll] is now a method, matching TypeScript. (0.335.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.335.0) - groups is now optional and cannot be null, matching TypeScript. (0.335.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.335.0) - RegExpStringIterator is now an interface, matching TypeScript. (0.335.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.335.0) - keyFor now returns string | void, matching TypeScript. (0.335.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.335.0) - Methods inherited from builtins such as typed arrays now return the subclass. (0.335.0) — [release notes](https://github.com/facebook/flow/releases/tag/v0.335.0)