facebook/flow v0.275.0

on GitHub

Likely to cause new Flow errors:

• For all object literals in positions that cannot be contextually typed, we will infer a stricter type for them. It will cause new errors in code like

const foo = {baz: new Dog()};
type Foo = {bar?: string, baz: Animal};
declare function acceptFoo(foo: Foo): void;
acceptFoo(foo); // error

To fix the error, you can either annotate the object

const foo: Foo = {baz: new Dog()};

type Foo = {bar?: string, baz: Animal};
declare function acceptFoo(foo: Foo): void;

acceptFoo(foo);

or make the call site accepts readonly objects:

const foo = {baz: new Dog()};

type Foo = $ReadOnly<{bar?: string, baz: Animal}>;
declare function acceptFoo(foo: Foo): void;

acceptFoo(foo);

We provide a codemod to automate the annotation process. flow codemod annotate-literal-declaration --write --max-type-size 5. (You can adjust the max type size based on your needs).

IDE:

• Support rename on private properties and methods.

Library Definitions:

• React$MixedElement is removed from builtin libdef. It will cause internal-type error since v0.258.0. You should use React.MixedElement instead.