Fix empty line check between array elements (prettier#14736)

Co-authored-by: ☀️ <sol@solfox.online>
Co-authored-by: fisker Cheung <lionkay@gmail.com>

changelog_unreleased/javascript/14736.md

@@ -0,0 +1,24 @@
+#### Fix empty line check between array elements (#14736 by @solarized-fox)
+
+<!-- prettier-ignore -->
+```jsx
+// Input
+[
+  (a = b),
+
+  c // comment
+]
+
+// Prettier stable
+[
+  (a = b),
+  c, // comment
+];
+
+// Prettier main
+[
+  (a = b),
+
+  c, // comment
+];
+```

src/language-js/print/array.js

@@ -9,17 +9,19 @@ import {
   fill,
 } from "../../document/builders.js";
 import hasNewline from "../../utils/has-newline.js";
+import isNextLineEmptyAfterIndex from "../../utils/is-next-line-empty.js";
+import skipInlineComment from "../../utils/skip-inline-comment.js";
+import skipTrailingComment from "../../utils/skip-trailing-comment.js";
 import {
   shouldPrintComma,
   hasComment,
   CommentCheckFlags,
-  isNextLineEmpty,
   isNumericLiteral,
   isSignedNumericLiteral,
   isArrayOrTupleExpression,
   isObjectOrRecordExpression,
 } from "../utils/index.js";
-import { locStart } from "../loc.js";
+import { locStart, locEnd } from "../loc.js";
 
 import { printOptionalToken } from "./misc.js";
 import { printTypeAnnotationProperty } from "./type-annotation.js";
@@ -170,6 +172,18 @@ function isConciselyPrintedArray(node, options) {
   );
 }
 
+function isLineAfterElementEmpty({ node }, { originalText: text }) {
+  const skipComment = (idx) =>
+    skipInlineComment(text, skipTrailingComment(text, idx));
+
+  const skipToComma = (currentIdx) =>
+    text[currentIdx] === ","
+      ? currentIdx
+      : skipToComma(skipComment(currentIdx + 1));
+
+  return isNextLineEmptyAfterIndex(text, skipToComma(locEnd(node)));
+}
+
 function printArrayElements(path, options, elementsProperty, print) {
   const parts = [];
 
@@ -180,7 +194,7 @@ function printArrayElements(path, options, elementsProperty, print) {
       parts.push([
         ",",
         line,
-        node && isNextLineEmpty(node, options) ? softline : "",
+        node && isLineAfterElementEmpty(path, options) ? softline : "",
       ]);
     }
   }, elementsProperty);
@@ -193,12 +207,12 @@ function printArrayElements(path, options, elementsProperty, print) {
 function printArrayElementsConcisely(path, options, print, trailingComma) {
   const parts = [];
 
-  path.each(({ node, isLast, next }) => {
+  path.each(({ isLast, next }) => {
     parts.push([print(), isLast ? trailingComma : ","]);
 
     if (!isLast) {
       parts.push(
-        isNextLineEmpty(node, options)
+        isLineAfterElementEmpty(path, options)
           ? [hardline, hardline]
           : hasComment(next, CommentCheckFlags.Leading | CommentCheckFlags.Line)
           ? hardline

tests/format/js/arrays/__snapshots__/jsfmt.spec.js.snap

@@ -778,6 +778,87 @@ a = [
 
 ]
 
+b = [
+  100,
+
+  (200)
+  ,
+
+  300
+  ,
+
+  1
+  ,
+  2, 3
+]
+
+c = [
+  "apple",
+  "banana",
+  "blueberry",
+
+  "red",
+  "blue"
+  ,
+  "yellow",
+
+  "broccoli",
+  "celery",
+  "lettuce"
+  ,
+
+  "green"
+  ,
+  "green",
+  "green",
+
+  //an egg
+  "egg",
+  //a bigger egg
+  "big egg"
+  //the biggest egg
+  ,
+  "huge egg"
+  ,
+
+  //not an egg
+  "lasagna"
+
+]
+
+_ = [
+  a,
+
+  b //
+]
+
+_ = [
+  (a),
+
+  b, //
+];
+
+_ = [
+  (((((
+    a = b/* comment */))/* comment */))),
+
+  c //
+]
+
+_ = [
+  (((((
+    (a = b)/* comment */))/* comment */))),
+
+  c //
+]
+
+_ = [
+  (a=b
+
+  ),
+  b, //
+];
+
 =====================================output=====================================
 a = [
   1, 2,
@@ -787,6 +868,60 @@ a = [
   4,
 ];
 
+b = [
+  100,
+
+  200,
+
+  300,
+
+  1, 2, 3,
+];
+
+c = [
+  "apple", "banana", "blueberry", "red", "blue", "yellow", "broccoli", "celery",
+  "lettuce", "green", "green", "green",
+
+  //an egg
+  "egg",
+  //a bigger egg
+  "big egg",
+  //the biggest egg
+  "huge egg",
+
+  //not an egg
+  "lasagna",
+];
+
+_ = [
+  a,
+
+  b, //
+];
+
+_ = [
+  a,
+
+  b, //
+];
+
+_ = [
+  (a = b) /* comment */ /* comment */,
+
+  c, //
+];
+
+_ = [
+  (a = b) /* comment */ /* comment */,
+
+  c, //
+];
+
+_ = [
+  (a = b),
+  b, //
+];
+
 ================================================================================
 `;
 

tests/format/js/arrays/preserve_empty_lines.js

@@ -10,3 +10,84 @@ a = [
 
 
 ]
+
+b = [
+  100,
+
+  (200)
+  ,
+
+  300
+  ,
+
+  1
+  ,
+  2, 3
+]
+
+c = [
+  "apple",
+  "banana",
+  "blueberry",
+
+  "red",
+  "blue"
+  ,
+  "yellow",
+
+  "broccoli",
+  "celery",
+  "lettuce"
+  ,
+
+  "green"
+  ,
+  "green",
+  "green",
+
+  //an egg
+  "egg",
+  //a bigger egg
+  "big egg"
+  //the biggest egg
+  ,
+  "huge egg"
+  ,
+
+  //not an egg
+  "lasagna"
+
+]
+
+_ = [
+  a,
+
+  b //
+]
+
+_ = [
+  (a),
+
+  b, //
+];
+
+_ = [
+  (((((
+    a = b/* comment */))/* comment */))),
+
+  c //
+]
+
+_ = [
+  (((((
+    (a = b)/* comment */))/* comment */))),
+
+  c //
+]
+
+_ = [
+  (a=b
+
+  ),
+  b, //
+];