From 4d89877bba37af973a87f66d365e25a9dda280ee Mon Sep 17 00:00:00 2001
From: Lucas Duailibe <lucasds@gmail.com>
Date: Mon, 16 Sep 2019 08:46:10 -0300
Subject: [PATCH] 1.19 blog post

---
 CHANGELOG.unreleased.md           | 583 -----------------------------
 website/blog/2019-09-16-1.19.0.md | 590 ++++++++++++++++++++++++++++++
 2 files changed, 590 insertions(+), 583 deletions(-)

diff --git a/CHANGELOG.unreleased.md b/CHANGELOG.unreleased.md
index 5ea0f757cfcc..538a5fec42a5 100644
--- a/CHANGELOG.unreleased.md
+++ b/CHANGELOG.unreleased.md
@@ -43,586 +43,3 @@ const link = <a href="example.com">http://example.com</a>;
 ```
 
 -->
-
-#### JavaScript: More readable parentheses for new-call ([#6412] by [@bakkot])
-
-<!-- prettier-ignore -->
-```js
-// Input
-var a = new (x().y)();
-var a = new (x().y.z)();
-var a = new (x().y().z)();
-
-// Output (Prettier stable)
-var a = new (x()).y();
-var a = new (x()).y.z();
-var a = new (x().y()).z();
-
-// Output (Prettier master)
-var a = new (x().y)();
-var a = new (x().y.z)();
-var a = new (x().y().z)();
-```
-
-#### MDX: fix text with whitespace after JSX trim incorrectly ([#6340] by [@JounQin])
-
-Previous versions format text with whitespace after JSX incorrectly in mdx, this has been fixed in this version.
-
-<!-- prettier-ignore -->
-```md
-<!-- Input -->
-# Heading
-<Hello>
-    test   <World />   test
-</Hello>       123
-
-<!-- Output (Prettier stable) -->
-<Hello>
-  test <World /> test
-</Hello>123
-
-<!-- Output (Prettier master) -->
-<Hello>
-  test <World /> test
-</Hello> 123
-```
-
-#### MDX: Adjacent JSX elements should be allowed in mdx ([#6332] by [@JounQin])
-
-Previous versions would not format adjacent JSX elements in mdx, this has been fixed in this version.
-
-<!-- prettier-ignore -->
-```jsx
-// Input
-<Hello>
-    test   <World />   test
-</Hello>123
-
-// Output (Prettier stable)
-SyntaxError: Unexpected token (3:9)
-  1 | <Hello>
-  2 |     test   <World />   test
-> 3 | </Hello>123
-    |         ^
-
-// Output (Prettier master)
-<Hello>
-  test <World /> test
-</Hello>123
-
-
-// Input
-<Hello>
-    test   <World />   test
-</Hello>
-<Hello>
-    test   <World />   test
-</Hello>123
-
-// Output (Prettier stable)
-SyntaxError: Adjacent JSX elements must be wrapped in an enclosing tag. Did you want a JSX fragment <>...</>? (4:1)
-  2 |     test   <World />   test
-  3 | </Hello>
-> 4 | <Hello>
-    | ^
-  5 |     test   <World />   test
-  6 | </Hello>123
-
-// Output (Prettier master)
-<Hello>
-  test <World /> test
-</Hello>
-<Hello>
-  test <World /> test
-</Hello>123
-```
-
-#### TypeScript: Print comment following a JSX element with generic ([#6209] by [@duailibe])
-
-Previous versions would not print this comment, this has been fixed in this version.
-
-<!-- prettier-ignore -->
-```ts
-// Input
-const comp = (
-  <Foo<number>
-    // This comment goes missing
-    value={4}
-  >
-    Test
-  </Foo>
-);
-
-// Output (Prettier stable)
-const comp = <Foo<number> value={4}>Test</Foo>;
-
-// Output (Prettier master)
-const comp = (
-  <Foo<number>
-    // This comment goes missing
-    value={4}
-  >
-    Test
-  </Foo>
-);
-```
-
-### Handlebars: Avoid adding unwanted line breaks between text and mustaches ([#6186] by [@gavinjoyce])
-
-Previously, Prettier added line breaks between text and mustaches which resulted in unwanted whitespace in rendered output.
-
-<!-- prettier-ignore -->
-```hbs
-// Input
-<p>Your username is @{{name}}</p>
-<p>Hi {{firstName}} {{lastName}}</p>
-
-// Output (Prettier stable)
-<p>
-  Your username is @
-  {{name}}
-</p>
-<p>
-  Hi
-  {{firstName}}
-  {{lastName}}
-</p>
-
-// Output (Prettier master)
-<p>
-  Your username is @{{name}}
-</p>
-<p>
-  Hi {{firstName}} {{lastName}}
-</p>
-```
-
-### Handlebars: Improve comment formatting ([#6206] by [@gavinjoyce])
-
-Previously, Prettier would sometimes ignore whitespace when formatting comments.
-
-<!-- prettier-ignore -->
-```hbs
-// Input
-<div>
-  {{! Foo }}
-  {{#if @foo}}
-    Foo
-  {{/if}}
-
-  {{! Bar }}
-  {{#if @bar}}
-    Bar
-  {{/if}}
-</div>
-
-// Output (Prettier stable)
-<div>
-  {{! Foo }}
-  {{#if @foo}}
-    Foo
-  {{/if}}{{! Bar }}{{#if @bar}}
-    Bar
-  {{/if}}
-</div>
-
-// Output (Prettier master)
-<div>
-  {{! Foo }}
-  {{#if @foo}}
-    Foo
-  {{/if}}
-  {{! Bar }}
-  {{#if @bar}}
-    Bar
-  {{/if}}
-</div>
-```
-
-#### JavaScript: Update ?? precedence to match stage 3 proposal ([#6404] by [@vjeux])
-
-We've updated Prettier's support for the nullish coalescing operator to match a spec update that no longer allows it to immediately contain, or be contained within an `&&` or `||` operation.
-
-<!-- prettier-ignore -->
-```js
-// Input
-(foo ?? baz) || baz;
-
-// Output (Prettier stable)
-foo ?? baz || baz;
-
-// Output (Prettier master)
-(foo ?? baz) || baz;
-```
-
-Please note, as we update our parsers with versions that support this spec update, code without the parenthesis will throw a parse error.
-
-#### JavaScript: Keep unary expressions parentheses with comments ([#6217] by [@sosukesuzuki])
-
-Previously, Prettier removes parentheses enclose unary expressions. This change modify to keep it when the expression has comments.
-
-<!-- prettier-ignore -->
-```ts
-// Input
-!(
-  /* foo */
-  foo
-);
-!(
-  foo // foo
-);
-
-// Output (Prettier stable)
-!/* foo */
-foo;
-!foo; // foo
-
-// Output (Prettier master)
-!(/* foo */ foo);
-!(
-  foo // foo
-);
-```
-
-### Handlebars: Improve comment formatting ([#6234] by [@gavinjoyce])
-
-Previously, Prettier would incorrectly decode HTML entiites.
-
-<!-- prettier-ignore -->
-```hbs
-// Input
-<p>
-  Some escaped characters: &lt; &gt; &amp;
-</p>
-
-// Output (Prettier stable)
-<p>
-  Some escaped characters: < > &
-</p>
-
-// Output (Prettier master)
-<p>
-  Some escaped characters: &lt; &gt; &amp;
-</p>
-```
-
-#### JavaScript: Stop moving comments inside tagged template literals ([#6236] by [@sosukesuzuki])
-
-Previously, Prettier would move comments after the tag inside the template literal. This version fixes this problem.
-
-<!-- prettier-ignore -->
-```js
-// Input
-foo //comment
-`
-`;
-
-// Output (Prettier stable)
-foo` // comment
-`;
-
-// Output (Prettier master)
-foo // comment
-`
-`;
-```
-
-#### JavaScript: Fix moving comments in function calls like `useEffect` second argument ([#6270] by [@sosukesuzuki])
-
-This fixes a bug that was affecting function calls that have a arrow function as first argument and an array expression as second argument, such as the common React's `useEffect`. A comment in its own line before the second argument would be moved to the line above.
-
-The bug was only present when using the Flow and TypeScript parsers.
-
-<!-- prettier-ignore -->
-```js
-// Input
-useEffect(
-  () => {
-    console.log("some code", props.foo);
-  },
-
-  // We need to disable the eslint warning here,
-  // because of some complicated reason.
-  // eslint-disable line react-hooks/exhaustive-deps
-  []
-);
-
-// Output (Prettier stable)
-useEffect(() => {
-  console.log("some code", props.foo);
-}, // We need to disable the eslint warning here,
-// because of some complicated reason.
-// eslint-disable line react-hooks/exhaustive-deps
-[]);
-
-// Output (Prettier master)
-useEffect(
-  () => {
-    console.log("some code", props.foo);
-  },
-
-  // We need to disable the eslint warning here,
-  // because of some complicated reason.
-  // eslint-disable line react-hooks/exhaustive-deps
-  []
-);
-```
-
-#### TypeScript: Fix crashes when using `//` in JSX texts ([#6289] by [@duailibe])
-
-This version updates the TypeScript parser to correctly handle JSX text with double slashes (`//`). In previous versions, this would cause Prettier to crash.
-
-#### CLI: Add `--only-changed` flag ([#5910] by [@g-harel])
-
-Flag used with `--write` to avoid re-checking files that were not changed since they were last written (with the same formatting configuration).
-
-#### HTML, Vue: Don't break the template element included in a line shorter than print-width([#6284] by [@sosukesuzuki])
-
-Previously, even if the line length is shorter than print-width is Prettier breaks the line with a template element.
-
-<!-- prettier-ignore -->
-```html
-// Input
-<template>
-  <template>foo</template>
-</template>
-
-// Output (Prettier stable)
-<template>
-  <template
-    >foo</template
-  >
-</template>
-
-// Output (Prettier master)
-<template>
-  <template>foo</template>
-</template>
-```
-
-#### JavaScript: Fix breaks indentation and idempotency when an arrow function that args include object pattern is passed to a function as parameter. ([#6301] by [@sosukesuzuki])
-
-Previously, Prettier collapses strangely, when an arrow function that args include object pattern is passed to a function as parameter. Also, it breaks idempotency. Please see [#6294](https://github.com/prettier/prettier/issues/6294) for detail.
-
-<!-- prettier-ignore -->
-```js
-// Input
-foo(
-  ({
-    a,
-
-    b
-  }) => {}
-);
-
-// Output (Prettier stable)
-foo(({ a,
-  b }) => {});
-
-// Output (Prettier master)
-foo(
-  ({
-    a,
-
-    b
-  }) => {}
-);
-```
-
-#### TypeScript: Fix specific union type breaks after opening parenthesis, but not before closing ([#6307] by [@sosukesuzuki])
-
-Previously, union type that put with `as` , `keyof`, `[]`, other union(`|`) and intersection(`&`) breaks after opening parenthesis, but not before closing. Please see [#6303](https://github.com/prettier/prettier/issues/6303) for detail.
-
-<!-- prettier-ignore-->
-```ts
-// Input
-const foo = [abc, def, ghi, jkl, mno, pqr, stu, vwx, yz] as (
-  | string
-  | undefined
-)[];
-
-// Prettier (stable)
-const foo = [abc, def, ghi, jkl, mno, pqr, stu, vwx, yz] as (
-  | string
-  | undefined)[];
-
-// Prettier (master)
-const foo = [abc, def, ghi, jkl, mno, pqr, stu, vwx, yz] as (
-  | string
-  | undefined
-)[];
-```
-
-#### HTML: Script tags are now treated as blocks for the purposes of formatting ([#6423] by [@thorn0])
-
-Previously, in the [whitespace-sensitive mode](https://prettier.io/docs/en/options.html#html-whitespace-sensitivity), they were formatted as if they were inline.
-
-<!-- prettier-ignore-->
-```html
-<!-- Input -->
-<script
-  async
-  src="/_next/static/development/pages/_app.js?ts=1565732195968"
-></script><script></script>
-
-<!-- Prettier (stable) -->
-<script
-  async
-  src="/_next/static/development/pages/_app.js?ts=1565732195968"
-></script
-><script></script>
-
-<!-- Prettier (master) -->
-<script
-  async
-  src="/_next/static/development/pages/_app.js?ts=1565732195968"
-></script>
-<script></script>
-```
-
-#### TypeScript: Fixed to break line and add a semicolon in one execution on one line long mapped types ([#6420] by [@sosukesuzuki])
-
-Previously, when Prettier formatted long, one-line mapped types, it would break the line but didn’t add a semicolon – until you ran Prettier again (which broke Prettier’s idempotency rule). Now, Prettier adds the semicolon in the first run, fixing the issue.
-
-<!-- prettier-ignore -->
-```ts
-// Input
-type FooBar<T> = { [P in keyof T]: T[P] extends Something ? Something<T[P]> : T[P] }
-
-// Prettier (stable)
-type FooBar<T> = {
-  [P in keyof T]: T[P] extends Something ? Something<T[P]> : T[P]
-};
-
-// Prettier (master)
-type FooBar<T> = {
-  [P in keyof T]: T[P] extends Something ? Something<T[P]> : T[P];
-};
-```
-
-#### JavaScript: Fix ugly formatting on object destructuring with parameter decorators ([#6411] by [@sosukesuzuki])
-
-Previously, Prettier formatted decorators for destructured parameters in a weird way. Now, parameter decorators are placed just above the parameter they belong to.
-
-<!-- prettier-ignore -->
-```js
-// Input
-class Class {
-  method(
-    @decorator
-     { foo }
-  ) {}
-}
-
-// Prettier (stable)
-class Class {
-  method(@decorator
-  {
-    foo
-  }) {}
-}
-
-// Prettier (master)
-class Class {
-  method(
-    @decorator
-    { foo }
-  ) {}
-}
-```
-
-#### JavaScript: Handle empty object patterns with type annotations in function parameters ([#6438] by [@bakkot])
-
-<!-- prettier-ignore -->
-```js
-// Input
-const f = ({}: MyVeryVeryVeryVeryVeryVeryVeryVeryVeryVeryVeryVeryVeryVeryLongType) => {};
-function g({}: Foo) {}
-
-// Output (Prettier stable)
-const f = ({
-  ,
-}: MyVeryVeryVeryVeryVeryVeryVeryVeryVeryVeryVeryVeryVeryVeryLongType) => {};
-function g({  }: Foo) {}
-
-// Output (Prettier master)
-const f = ({}: MyVeryVeryVeryVeryVeryVeryVeryVeryVeryVeryVeryVeryVeryVeryLongType) => {};
-function g({}: Foo) {}
-```
-
-#### JavaScript: Fix ugly formatting parens wrap binary expressions within call expressions ([#6441] by [@sosukesuzuki])
-
-Previously, Prettier formatted parens wrap binary expressions within call expressions in a weird way. There was no line break before and after each parens.
-
-<!-- prettier-ignore -->
-```js
-(
-  aaaaaaaaaaaaaaaaaaaaaaaaa &&
-  bbbbbbbbbbbbbbbbbbbbbbbbb &&
-  ccccccccccccccccccccccccc &&
-  ddddddddddddddddddddddddd &&
-  eeeeeeeeeeeeeeeeeeeeeeeee
-)();
-
-// Prettier (stable)
-(aaaaaaaaaaaaaaaaaaaaaaaaa &&
-  bbbbbbbbbbbbbbbbbbbbbbbbb &&
-  ccccccccccccccccccccccccc &&
-  ddddddddddddddddddddddddd &&
-  eeeeeeeeeeeeeeeeeeeeeeeee)();
-
-// Prettier (master)
-(
-  aaaaaaaaaaaaaaaaaaaaaaaaa &&
-  bbbbbbbbbbbbbbbbbbbbbbbbb &&
-  ccccccccccccccccccccccccc &&
-  ddddddddddddddddddddddddd &&
-  eeeeeeeeeeeeeeeeeeeeeeeee
-)();
-```
-
-#### JavaScript: Fix formatting on long named exports ([#6446] by [@sosukesuzuki])
-
-Previously, Prettier formatted long named exports differently than named imports.
-
-```js
-// Input
-export { fooooooooooooooooooooooooooooooooooooooooooooooooo } from "fooooooooooooooooooooooooooooo";
-
-// Prettier (stable)
-export {
-  fooooooooooooooooooooooooooooooooooooooooooooooooo
-} from "fooooooooooooooooooooooooooooo";
-
-// Prettier (master)
-export { fooooooooooooooooooooooooooooooooooooooooooooooooo } from "fooooooooooooooooooooooooooooo";
-```
-
-[#5910]: https://github.com/prettier/prettier/pull/5910
-[#6186]: https://github.com/prettier/prettier/pull/6186
-[#6206]: https://github.com/prettier/prettier/pull/6206
-[#6209]: https://github.com/prettier/prettier/pull/6209
-[#6217]: https://github.com/prettier/prettier/pull/6217
-[#6234]: https://github.com/prettier/prettier/pull/6234
-[#6236]: https://github.com/prettier/prettier/pull/6236
-[#6270]: https://github.com/prettier/prettier/pull/6270
-[#6289]: https://github.com/prettier/prettier/pull/6289
-[#6332]: https://github.com/prettier/prettier/pull/6332
-[#6284]: https://github.com/prettier/prettier/pull/6284
-[#6301]: https://github.com/prettier/prettier/pull/6301
-[#6307]: https://github.com/prettier/prettier/pull/6307
-[#6340]: https://github.com/prettier/prettier/pull/6340
-[#6412]: https://github.com/prettier/prettier/pull/6412
-[#6423]: https://github.com/prettier/prettier/pull/6423
-[#6420]: https://github.com/prettier/prettier/pull/6420
-[#6411]: https://github.com/prettier/prettier/pull/6411
-[#6438]: https://github.com/prettier/prettier/pull/6411
-[#6441]: https://github.com/prettier/prettier/pull/6441
-[#6446]: https://github.com/prettier/prettier/pull/6446
-[@duailibe]: https://github.com/duailibe
-[@gavinjoyce]: https://github.com/gavinjoyce
-[@sosukesuzuki]: https://github.com/sosukesuzuki
-[@g-harel]: https://github.com/g-harel
-[@jounqin]: https://github.com/JounQin
-[@bakkot]: https://gibhub.com/bakkot
-[@thorn0]: https://github.com/thorn0
diff --git a/website/blog/2019-09-16-1.19.0.md b/website/blog/2019-09-16-1.19.0.md
index e69de29bb2d1..23e3592135d5 100644
--- a/website/blog/2019-09-16-1.19.0.md
+++ b/website/blog/2019-09-16-1.19.0.md
@@ -0,0 +1,590 @@
+### JavaScript
+
+#### More readable parentheses for new-call ([#6412] by [@bakkot])
+
+<!-- prettier-ignore -->
+```js
+// Input
+var a = new (x().y)();
+var a = new (x().y.z)();
+var a = new (x().y().z)();
+
+// Output (Prettier 1.18)
+var a = new (x()).y();
+var a = new (x()).y.z();
+var a = new (x().y()).z();
+
+// Output (Prettier 1.19)
+var a = new (x().y)();
+var a = new (x().y.z)();
+var a = new (x().y().z)();
+```
+
+#### Update ?? precedence to match stage 3 proposal ([#6404] by [@vjeux])
+
+We've updated Prettier's support for the nullish coalescing operator to match a spec update that no longer allows it to immediately contain, or be contained within an `&&` or `||` operation.
+
+<!-- prettier-ignore -->
+```js
+// Input
+(foo ?? baz) || baz;
+
+// Output (Prettier 1.18)
+foo ?? baz || baz;
+
+// Output (Prettier 1.19)
+(foo ?? baz) || baz;
+```
+
+Please note, as we update our parsers with versions that support this spec update, code without the parenthesis will throw a parse error.
+
+#### Fix ugly formatting on object destructuring with parameter decorators ([#6411] by [@sosukesuzuki])
+
+Previously, Prettier formatted decorators for destructured parameters in a weird way. Now, parameter decorators are placed just above the parameter they belong to.
+
+<!-- prettier-ignore -->
+```js
+// Input
+class Class {
+  method(
+    @decorator
+     { foo }
+  ) {}
+}
+
+// Prettier (stable)
+class Class {
+  method(@decorator
+  {
+    foo
+  }) {}
+}
+
+// Prettier (master)
+class Class {
+  method(
+    @decorator
+    { foo }
+  ) {}
+}
+```
+
+#### Handle empty object patterns with type annotations in function parameters ([#6438] by [@bakkot])
+
+<!-- prettier-ignore -->
+```js
+// Input
+const f = ({}: MyVeryVeryVeryVeryVeryVeryVeryVeryVeryVeryVeryVeryVeryVeryLongType) => {};
+function g({}: Foo) {}
+
+// Output (Prettier 1.18)
+const f = ({
+  ,
+}: MyVeryVeryVeryVeryVeryVeryVeryVeryVeryVeryVeryVeryVeryVeryLongType) => {};
+function g({  }: Foo) {}
+
+// Output (Prettier 1.19)
+const f = ({}: MyVeryVeryVeryVeryVeryVeryVeryVeryVeryVeryVeryVeryVeryVeryLongType) => {};
+function g({}: Foo) {}
+```
+
+#### Fix ugly formatting parens wrap binary expressions within call expressions ([#6441] by [@sosukesuzuki])
+
+Previously, Prettier formatted parens wrap binary expressions within call expressions in a weird way. There was no line break before and after each parens.
+
+<!-- prettier-ignore -->
+```js
+(
+  aaaaaaaaaaaaaaaaaaaaaaaaa &&
+  bbbbbbbbbbbbbbbbbbbbbbbbb &&
+  ccccccccccccccccccccccccc &&
+  ddddddddddddddddddddddddd &&
+  eeeeeeeeeeeeeeeeeeeeeeeee
+)();
+
+// Prettier (stable)
+(aaaaaaaaaaaaaaaaaaaaaaaaa &&
+  bbbbbbbbbbbbbbbbbbbbbbbbb &&
+  ccccccccccccccccccccccccc &&
+  ddddddddddddddddddddddddd &&
+  eeeeeeeeeeeeeeeeeeeeeeeee)();
+
+// Prettier (master)
+(
+  aaaaaaaaaaaaaaaaaaaaaaaaa &&
+  bbbbbbbbbbbbbbbbbbbbbbbbb &&
+  ccccccccccccccccccccccccc &&
+  ddddddddddddddddddddddddd &&
+  eeeeeeeeeeeeeeeeeeeeeeeee
+)();
+```
+
+#### Fix formatting on long named exports ([#6446] by [@sosukesuzuki])
+
+Previously, Prettier formatted long named exports differently than named imports.
+
+```js
+// Input
+export { fooooooooooooooooooooooooooooooooooooooooooooooooo } from "fooooooooooooooooooooooooooooo";
+
+// Prettier (stable)
+export {
+  fooooooooooooooooooooooooooooooooooooooooooooooooo
+} from "fooooooooooooooooooooooooooooo";
+
+// Prettier (master)
+export { fooooooooooooooooooooooooooooooooooooooooooooooooo } from "fooooooooooooooooooooooooooooo";
+```
+
+#### Fix breaks indentation and idempotency when an arrow function that args include object pattern is passed to a function as parameter. ([#6301] by [@sosukesuzuki])
+
+Previously, Prettier collapses strangely, when an arrow function that args include object pattern is passed to a function as parameter. Also, it breaks idempotency. Please see [#6294](https://github.com/prettier/prettier/issues/6294) for detail.
+
+<!-- prettier-ignore -->
+```js
+// Input
+foo(
+  ({
+    a,
+
+    b
+  }) => {}
+);
+
+// Output (Prettier 1.18)
+foo(({ a,
+  b }) => {});
+
+// Output (Prettier 1.19)
+foo(
+  ({
+    a,
+
+    b
+  }) => {}
+);
+```
+
+#### Keep unary expressions parentheses with comments ([#6217] by [@sosukesuzuki])
+
+Previously, Prettier removes parentheses enclose unary expressions. This change modify to keep it when the expression has comments.
+
+<!-- prettier-ignore -->
+```ts
+// Input
+!(
+  /* foo */
+  foo
+);
+!(
+  foo // foo
+);
+
+// Output (Prettier 1.18)
+!/* foo */
+foo;
+!foo; // foo
+
+// Output (Prettier 1.19)
+!(/* foo */ foo);
+!(
+  foo // foo
+);
+```
+
+#### Stop moving comments inside tagged template literals ([#6236] by [@sosukesuzuki])
+
+Previously, Prettier would move comments after the tag inside the template literal. This version fixes this problem.
+
+<!-- prettier-ignore -->
+```js
+// Input
+foo //comment
+`
+`;
+
+// Output (Prettier 1.18)
+foo` // comment
+`;
+
+// Output (Prettier 1.19)
+foo // comment
+`
+`;
+```
+
+#### Fix moving comments in function calls like `useEffect` second argument ([#6270] by [@sosukesuzuki])
+
+This fixes a bug that was affecting function calls that have a arrow function as first argument and an array expression as second argument, such as the common React's `useEffect`. A comment in its own line before the second argument would be moved to the line above.
+
+The bug was only present when using the Flow and TypeScript parsers.
+
+<!-- prettier-ignore -->
+```js
+// Input
+useEffect(
+  () => {
+    console.log("some code", props.foo);
+  },
+
+  // We need to disable the eslint warning here,
+  // because of some complicated reason.
+  // eslint-disable line react-hooks/exhaustive-deps
+  []
+);
+
+// Output (Prettier 1.18)
+useEffect(() => {
+  console.log("some code", props.foo);
+}, // We need to disable the eslint warning here,
+// because of some complicated reason.
+// eslint-disable line react-hooks/exhaustive-deps
+[]);
+
+// Output (Prettier 1.19)
+useEffect(
+  () => {
+    console.log("some code", props.foo);
+  },
+
+  // We need to disable the eslint warning here,
+  // because of some complicated reason.
+  // eslint-disable line react-hooks/exhaustive-deps
+  []
+);
+```
+
+### TypeScript
+
+#### Print comment following a JSX element with generic ([#6209] by [@duailibe])
+
+Previous versions would not print this comment, this has been fixed in this version.
+
+<!-- prettier-ignore -->
+```ts
+// Input
+const comp = (
+  <Foo<number>
+    // This comment goes missing
+    value={4}
+  >
+    Test
+  </Foo>
+);
+
+// Output (Prettier 1.18)
+const comp = <Foo<number> value={4}>Test</Foo>;
+
+// Output (Prettier 1.19)
+const comp = (
+  <Foo<number>
+    // This comment goes missing
+    value={4}
+  >
+    Test
+  </Foo>
+);
+```
+
+#### Fix crashes when using `//` in JSX texts ([#6289] by [@duailibe])
+
+This version updates the TypeScript parser to correctly handle JSX text with double slashes (`//`). In previous versions, this would cause Prettier to crash.
+
+#### Fix specific union type breaks after opening parenthesis, but not before closing ([#6307] by [@sosukesuzuki])
+
+Previously, union type that put with `as` , `keyof`, `[]`, other union(`|`) and intersection(`&`) breaks after opening parenthesis, but not before closing. Please see [#6303](https://github.com/prettier/prettier/issues/6303) for detail.
+
+<!-- prettier-ignore-->
+```ts
+// Input
+const foo = [abc, def, ghi, jkl, mno, pqr, stu, vwx, yz] as (
+  | string
+  | undefined
+)[];
+
+// Prettier (stable)
+const foo = [abc, def, ghi, jkl, mno, pqr, stu, vwx, yz] as (
+  | string
+  | undefined)[];
+
+// Prettier (master)
+const foo = [abc, def, ghi, jkl, mno, pqr, stu, vwx, yz] as (
+  | string
+  | undefined
+)[];
+```
+
+#### Fixed to break line and add a semicolon in one execution on one line long mapped types ([#6420] by [@sosukesuzuki])
+
+Previously, when Prettier formatted long, one-line mapped types, it would break the line but didn’t add a semicolon – until you ran Prettier again (which broke Prettier’s idempotency rule). Now, Prettier adds the semicolon in the first run, fixing the issue.
+
+<!-- prettier-ignore -->
+```ts
+// Input
+type FooBar<T> = { [P in keyof T]: T[P] extends Something ? Something<T[P]> : T[P] }
+
+// Prettier (stable)
+type FooBar<T> = {
+  [P in keyof T]: T[P] extends Something ? Something<T[P]> : T[P]
+};
+
+// Prettier (master)
+type FooBar<T> = {
+  [P in keyof T]: T[P] extends Something ? Something<T[P]> : T[P];
+};
+```
+
+### MDX
+
+#### Fix text with whitespace after JSX trim incorrectly ([#6340] by [@JounQin])
+
+Previous versions format text with whitespace after JSX incorrectly in mdx, this has been fixed in this version.
+
+<!-- prettier-ignore -->
+```md
+<!-- Input -->
+# Heading
+<Hello>
+    test   <World />   test
+</Hello>       123
+
+<!-- Output (Prettier 1.18) -->
+<Hello>
+  test <World /> test
+</Hello>123
+
+<!-- Output (Prettier 1.19) -->
+<Hello>
+  test <World /> test
+</Hello> 123
+```
+
+#### Adjacent JSX elements should be allowed in mdx ([#6332] by [@JounQin])
+
+Previous versions would not format adjacent JSX elements in mdx, this has been fixed in this version.
+
+<!-- prettier-ignore -->
+```jsx
+// Input
+<Hello>
+    test   <World />   test
+</Hello>123
+
+// Output (Prettier 1.18)
+SyntaxError: Unexpected token (3:9)
+  1 | <Hello>
+  2 |     test   <World />   test
+> 3 | </Hello>123
+    |         ^
+
+// Output (Prettier 1.19)
+<Hello>
+  test <World /> test
+</Hello>123
+
+
+// Input
+<Hello>
+    test   <World />   test
+</Hello>
+<Hello>
+    test   <World />   test
+</Hello>123
+
+// Output (Prettier 1.18)
+SyntaxError: Adjacent JSX elements must be wrapped in an enclosing tag. Did you want a JSX fragment <>...</>? (4:1)
+  2 |     test   <World />   test
+  3 | </Hello>
+> 4 | <Hello>
+    | ^
+  5 |     test   <World />   test
+  6 | </Hello>123
+
+// Output (Prettier 1.19)
+<Hello>
+  test <World /> test
+</Hello>
+<Hello>
+  test <World /> test
+</Hello>123
+```
+
+### Handlebars
+
+#### Avoid adding unwanted line breaks between text and mustaches ([#6186] by [@gavinjoyce])
+
+Previously, Prettier added line breaks between text and mustaches which resulted in unwanted whitespace in rendered output.
+
+<!-- prettier-ignore -->
+```hbs
+// Input
+<p>Your username is @{{name}}</p>
+<p>Hi {{firstName}} {{lastName}}</p>
+
+// Output (Prettier 1.18)
+<p>
+  Your username is @
+  {{name}}
+</p>
+<p>
+  Hi
+  {{firstName}}
+  {{lastName}}
+</p>
+
+// Output (Prettier 1.19)
+<p>
+  Your username is @{{name}}
+</p>
+<p>
+  Hi {{firstName}} {{lastName}}
+</p>
+```
+
+#### Improve comment formatting ([#6206] by [@gavinjoyce])
+
+Previously, Prettier would sometimes ignore whitespace when formatting comments.
+
+<!-- prettier-ignore -->
+```hbs
+// Input
+<div>
+  {{! Foo }}
+  {{#if @foo}}
+    Foo
+  {{/if}}
+
+  {{! Bar }}
+  {{#if @bar}}
+    Bar
+  {{/if}}
+</div>
+
+// Output (Prettier 1.18)
+<div>
+  {{! Foo }}
+  {{#if @foo}}
+    Foo
+  {{/if}}{{! Bar }}{{#if @bar}}
+    Bar
+  {{/if}}
+</div>
+
+// Output (Prettier 1.19)
+<div>
+  {{! Foo }}
+  {{#if @foo}}
+    Foo
+  {{/if}}
+  {{! Bar }}
+  {{#if @bar}}
+    Bar
+  {{/if}}
+</div>
+```
+
+### Handlebars: Improve comment formatting ([#6234] by [@gavinjoyce])
+
+Previously, Prettier would incorrectly decode HTML entiites.
+
+<!-- prettier-ignore -->
+```hbs
+// Input
+<p>
+  Some escaped characters: &lt; &gt; &amp;
+</p>
+
+// Output (Prettier 1.18)
+<p>
+  Some escaped characters: < > &
+</p>
+
+// Output (Prettier 1.19)
+<p>
+  Some escaped characters: &lt; &gt; &amp;
+</p>
+```
+
+#### CLI: Add `--only-changed` flag ([#5910] by [@g-harel])
+
+Flag used with `--write` to avoid re-checking files that were not changed since they were last written (with the same formatting configuration).
+
+#### HTML, Vue: Don't break the template element included in a line shorter than print-width([#6284] by [@sosukesuzuki])
+
+Previously, even if the line length is shorter than print-width is Prettier breaks the line with a template element.
+
+<!-- prettier-ignore -->
+```html
+// Input
+<template>
+  <template>foo</template>
+</template>
+
+// Output (Prettier 1.18)
+<template>
+  <template
+    >foo</template
+  >
+</template>
+
+// Output (Prettier 1.19)
+<template>
+  <template>foo</template>
+</template>
+```
+
+#### HTML: Script tags are now treated as blocks for the purposes of formatting ([#6423] by [@thorn0])
+
+Previously, in the [whitespace-sensitive mode](https://prettier.io/docs/en/options.html#html-whitespace-sensitivity), they were formatted as if they were inline.
+
+<!-- prettier-ignore-->
+```html
+<!-- Input -->
+<script
+  async
+  src="/_next/static/development/pages/_app.js?ts=1565732195968"
+></script><script></script>
+
+<!-- Prettier (stable) -->
+<script
+  async
+  src="/_next/static/development/pages/_app.js?ts=1565732195968"
+></script
+><script></script>
+
+<!-- Prettier (master) -->
+<script
+  async
+  src="/_next/static/development/pages/_app.js?ts=1565732195968"
+></script>
+<script></script>
+```
+
+[#5910]: https://github.com/prettier/prettier/pull/5910
+[#6186]: https://github.com/prettier/prettier/pull/6186
+[#6206]: https://github.com/prettier/prettier/pull/6206
+[#6209]: https://github.com/prettier/prettier/pull/6209
+[#6217]: https://github.com/prettier/prettier/pull/6217
+[#6234]: https://github.com/prettier/prettier/pull/6234
+[#6236]: https://github.com/prettier/prettier/pull/6236
+[#6270]: https://github.com/prettier/prettier/pull/6270
+[#6289]: https://github.com/prettier/prettier/pull/6289
+[#6332]: https://github.com/prettier/prettier/pull/6332
+[#6284]: https://github.com/prettier/prettier/pull/6284
+[#6301]: https://github.com/prettier/prettier/pull/6301
+[#6307]: https://github.com/prettier/prettier/pull/6307
+[#6340]: https://github.com/prettier/prettier/pull/6340
+[#6412]: https://github.com/prettier/prettier/pull/6412
+[#6423]: https://github.com/prettier/prettier/pull/6423
+[#6420]: https://github.com/prettier/prettier/pull/6420
+[#6411]: https://github.com/prettier/prettier/pull/6411
+[#6438]: https://github.com/prettier/prettier/pull/6411
+[#6441]: https://github.com/prettier/prettier/pull/6441
+[#6446]: https://github.com/prettier/prettier/pull/6446
+[@duailibe]: https://github.com/duailibe
+[@gavinjoyce]: https://github.com/gavinjoyce
+[@sosukesuzuki]: https://github.com/sosukesuzuki
+[@g-harel]: https://github.com/g-harel
+[@jounqin]: https://github.com/JounQin
+[@bakkot]: https://gibhub.com/bakkot
+[@thorn0]: https://github.com/thorn0