Merge branch 'master' into feat/array-style

Author: gajus

.README/README.md

@@ -122,6 +122,12 @@ To enable this configuration use the extends property in your `.eslintrc` config
 
 See [ESLint documentation](http://eslint.org/docs/user-guide/configuring#extending-configuration-files) for more information about extending configuration files.
 
+### Community maintained configurations
+
+The following are third-party submitted/ maintained configurations of `eslint-plugin-flowtype`:
+
+* https://github.com/wemake-services/eslint-config-flowtype-essential
+
 ## Settings
 
 ### `onlyFilesWithFlowAnnotation`
@@ -148,14 +154,20 @@ When `true`, only checks files with a [`@flow` annotation](http://flowtype.org/d
 {"gitdown": "include", "file": "./rules/define-flow-type.md"}
 {"gitdown": "include", "file": "./rules/delimiter-dangle.md"}
 {"gitdown": "include", "file": "./rules/generic-spacing.md"}
+{"gitdown": "include", "file": "./rules/newline-after-flow-annotation"}
 {"gitdown": "include", "file": "./rules/no-dupe-keys.md"}
+{"gitdown": "include", "file": "./rules/no-existential-type.md"}
+{"gitdown": "include", "file": "./rules/no-flow-fix-me-comments.md"}
+{"gitdown": "include", "file": "./rules/no-mutable-array.md"}
 {"gitdown": "include", "file": "./rules/no-primitive-constructor-types.md"}
 {"gitdown": "include", "file": "./rules/no-types-missing-file-annotation.md"}
 {"gitdown": "include", "file": "./rules/no-unused-expressions.md"}
 {"gitdown": "include", "file": "./rules/no-weak-types.md"}
 {"gitdown": "include", "file": "./rules/object-type-delimiter.md"}
+{"gitdown": "include", "file": "./rules/require-exact-type.md"}
 {"gitdown": "include", "file": "./rules/require-parameter-type.md"}
 {"gitdown": "include", "file": "./rules/require-return-type.md"}
+{"gitdown": "include", "file": "./rules/require-types-at-top.md"}
 {"gitdown": "include", "file": "./rules/require-valid-file-annotation.md"}
 {"gitdown": "include", "file": "./rules/require-variable-type.md"}
 {"gitdown": "include", "file": "./rules/semi.md"}
@@ -164,6 +176,7 @@ When `true`, only checks files with a [`@flow` annotation](http://flowtype.org/d
 {"gitdown": "include", "file": "./rules/space-before-generic-bracket.md"}
 {"gitdown": "include", "file": "./rules/space-before-type-colon.md"}
 {"gitdown": "include", "file": "./rules/type-id-match.md"}
+{"gitdown": "include", "file": "./rules/type-import-style.md"}
 {"gitdown": "include", "file": "./rules/union-intersection-spacing.md"}
 {"gitdown": "include", "file": "./rules/use-flow-type.md"}
 {"gitdown": "include", "file": "./rules/valid-syntax.md"}

.README/rules/newline-after-flow-annotation.md

@@ -0,0 +1,25 @@
+### `newline-after-flow-annotation`
+
+This rule requires an empty line after the Flow annotation.
+
+#### Options
+
+The rule has a string option:
+
+* `"always"` (default): Enforces that `@flow` annotations be followed by an empty line, separated by newline (LF)
+* `"always-windows"`: Identical to "always", but will use a CRLF when autofixing
+* `"never"`: Enforces that `@flow` annotations are not followed by empty lines
+
+```js
+{
+ "rules": {
+ "flowtype/newline-after-flow-annotation": [
+ 2,
+ "always"
+ ]
+ }
+}
+```
+
+
+<!-- assertions newlineAfterFlowAnnotation -->

.README/rules/no-existential-type.md

@@ -0,0 +1,15 @@
+### `no-existential-type`
+
+Disallows use of the existential type (*). [See more](https://flow.org/en/docs/types/utilities/#toc-existential-type)
+
+```js
+{
+ "rules": {
+ "flowtype/no-existential-type": 2
+ }
+}
+```
+
+
+<!-- assertions newlineAfterFlowAnnotation -->
+

.README/rules/no-flow-fix-me-comments.md

@@ -0,0 +1,22 @@
+### `no-flow-fix-me-comments`
+
+Disallows `$FlowFixMe` comment suppressions.
+
+This is especially useful as a warning to ensure instances of `$FlowFixMe` in your codebase get fixed over time.
+
+#### Options
+
+This rule takes an optional RegExp that comments a text RegExp that makes the supression valid.
+
+```js
+{
+ "rules": {
+ "flowtype/no-flow-fix-me-comments": [
+ 1,
+ "TODO\s+[0-9]+"
+ ]
+ }
+}
+```
+
+<!-- assertions no-flow-fix-me-comments -->

.README/rules/no-mutable-array.md

@@ -0,0 +1,16 @@
+### `no-mutable-array`
+
+_The `--fix` option on the command line automatically fixes problems reported by this rule._
+
+Requires use of [`$ReadOnlyArray`](https://github.com/facebook/flow/blob/v0.46.0/lib/core.js#L185) instead of just `Array` or array [shorthand notation](https://flow.org/en/docs/types/arrays/#toc-array-type-shorthand-syntax). `$ReadOnlyArray` is immutable array collection type and the superclass of Array and tuple types in Flow. Use of `$ReadOnlyArray` instead of `Array` can solve some "problems" in typing with Flow (e.g., [1](https://github.com/facebook/flow/issues/3425), [2](https://github.com/facebook/flow/issues/4251)).
+
+General reasons for using immutable data structures:
+
+* They are simpler to construct, test, and use
+* They help to avoid temporal coupling
+* Their usage is side-effect free (no defensive copies)
+* Identity mutability problem is avoided
+* They always have failure atomicity
+* They are much easier to cache
+
+<!-- assertions noMutableArray -->

.README/rules/require-exact-type.md

@@ -0,0 +1,32 @@
+### `require-exact-type`
+
+This rule enforces [exact object types](https://flow.org/en/docs/types/objects/#toc-exact-object-types).
+
+#### Options
+
+The rule has one string option:
+
+* `"always"` (default): Report all object type definitions that aren't exact.
+* `"never"`: Report all object type definitions that are exact.
+
+```js
+{
+ "rules": {
+ "flowtype/require-exact-type": [
+ 2,
+ "always"
+ ]
+ }
+}
+
+{
+ "rules": {
+ "flowtype/require-exact-type": [
+ 2,
+ "never"
+ ]
+ }
+}
+```
+
+<!-- assertions requireExactType -->

.README/rules/require-types-at-top.md

@@ -0,0 +1,14 @@
+### `require-types-at-top`
+
+Requires all type declarations to be at the top of the file, after any import declarations.
+
+#### Options
+
+The rule has a string option:
+
+* `"never"`
+* `"always"`
+
+The default value is `"always"`.
+
+<!-- assertions require-types-at-top -->

.README/rules/sort-keys.md

@@ -1,5 +1,7 @@
 ### `sort-keys`
 
+_The `--fix` option on the command line automatically fixes problems reported by this rule._
+
 Enforces sorting of Object annotations.
 
 This rule mirrors ESlint's [sort-keys](http://eslint.org/docs/rules/sort-keys) rule.

.README/rules/type-import-style.md

@@ -0,0 +1,22 @@
+### `type-import-style`
+
+_The `--fix` option on the command line automatically fixes problems reported by this rule._
+
+Enforces a particular style for type imports:
+
+```
+// 'identifier' style
+import {type T, type U, type V} from '...';
+
+// 'declaration' style
+import type {T, U, V} from '...';
+```
+
+The rule has a string option:
+
+* `"identifier"` (default): Enforces that type imports are all in the
+ 'identifier' style.
+* `"declaration"`: Enforces that type imports are all in the 'declaration'
+ style.
+
+<!-- assertions typeImportStyle -->

CONTRIBUTING.md

@@ -36,13 +36,13 @@ Run with `npm run lint`.
 
 1. Create a file in `tests/rules/assertions` named the `camelCase` version of your rule name with the following template:
  * `export default { invalid: [], valid: [] }`
-2. Add your test file to `tests/index.js`
+2. Add your test file to `tests/rules/index.js`
 3. Create a file in `src/rules` named the `camelCase` version of your rule name
 4. Add your rule file to `src/index.js`
 
 ### Adding Documentation
 
-1. Create new file in `./README/rules/[rule-name].md`.
+1. Create new file in `./.README/rules/[rule-name].md`.
  * Use [./.README/rules/require-valid-file-annotation.md](./.README/rules/require-valid-file-annotation.md) as a template.
  * Ensure that rule documentation document includes `<!-- assertions spaceAfterTypeColon -->` declaration.
 1. Update [./.README/README.md](/.README/README.md) to include the new rule.