Fix repositioning the cursor at the end of a range format (#10938)

* Adjust the upper bound on cursorOffset when range formatting

* fix implementation

* Add changelog entry

* Update changelog entry to use PR number

changelog_unreleased/javascript/10938.md

@@ -0,0 +1,19 @@
+#### Track cursor position properly when it’s at the end of the range to format (#10938 by @j-f1)
+
+Previously, if the cursor was at the end of the range to format, it would simply be placed back at the end of the updated range.
+Now, it will be repositioned if Prettier decides to add additional code to the end of the range (such as a semicolon).
+
+<!-- prettier-ignore -->
+```jsx
+// Input (<|> represents the cursor)
+const someVariable = myOtherVariable<|>
+// range to format:  ^^^^^^^^^^^^^^^
+
+// Prettier stable
+const someVariable = myOtherVariable;<|>
+// range to format:  ^^^^^^^^^^^^^^^
+
+// Prettier main
+const someVariable = myOtherVariable<|>;
+// range to format:  ^^^^^^^^^^^^^^^
+```

src/main/core.js

@@ -168,7 +168,7 @@ function formatRange(originalText, opts) {
       rangeEnd: Number.POSITIVE_INFINITY,
       // Track the cursor offset only if it's within our range
       cursorOffset:
-        opts.cursorOffset > rangeStart && opts.cursorOffset < rangeEnd
+        opts.cursorOffset > rangeStart && opts.cursorOffset <= rangeEnd
           ? opts.cursorOffset - rangeStart
           : -1,
       // Always use `lf` to format, we'll replace it later
@@ -182,7 +182,7 @@ function formatRange(originalText, opts) {
   const rangeTrimmed = rangeResult.formatted.trimEnd();
 
   let { cursorOffset } = opts;
-  if (cursorOffset >= rangeEnd) {
+  if (cursorOffset > rangeEnd) {
     // handle the case where the cursor was past the end of the range
     cursorOffset += rangeTrimmed.length - rangeString.length;
   } else if (rangeResult.cursorOffset >= 0) {

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

@@ -445,3 +445,86 @@ thisWontBeFormatted  ( 1  ,3)
     
 ================================================================================
 `;
+
+exports[`range-5.js format 1`] = `
+====================================options=====================================
+cursorOffset: 23
+parsers: ["babel", "typescript", "flow"]
+printWidth: 80
+rangeEnd: 23
+rangeStart: 14
+     |                                                                                | printWidth
+=====================================input======================================
+> 1 | const myVar = aFunction<|>
+    |               ^^^^^^^^^
+  2 |
+=====================================output=====================================
+const myVar = aFunction<|>;
+
+================================================================================
+`;
+
+exports[`range-6.js format 1`] = `
+====================================options=====================================
+cursorOffset: 24
+parsers: ["babel", "typescript", "flow"]
+printWidth: 80
+rangeEnd: 24
+rangeStart: 14
+     |                                                                                | printWidth
+=====================================input======================================
+> 1 | const myVar = aFunction;<|>
+    |               ^^^^^^^^^^
+  2 |
+=====================================output=====================================
+const myVar = aFunction;<|>
+
+================================================================================
+`;
+
+exports[`range-7.js format 1`] = `
+====================================options=====================================
+cursorOffset: 23
+parsers: ["babel", "typescript", "flow"]
+printWidth: 80
+rangeEnd: 24
+rangeStart: 14
+     |                                                                                | printWidth
+=====================================input======================================
+> 1 | const myVar = aFunction<|>;
+    |               ^^^^^^^^^^^^^
+  2 |
+=====================================output=====================================
+const myVar = aFunction<|>;
+
+================================================================================
+`;
+
+exports[`range-8.js format 1`] = `
+====================================options=====================================
+cursorOffset: 69
+parsers: ["babel", "typescript", "flow"]
+printWidth: 80
+rangeEnd: 72
+rangeStart: 30
+     |                                                                                | printWidth
+=====================================input======================================
+  1 | thisWontBeFormatted  ( 1  ,3)
+> 2 |
+    | ^
+> 3 |     thisWillBeFormatted    (2  ,3,   )<|>
+    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+> 4 |
+    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+> 5 |     thisWontBeFormatted  (2, 90  ,)
+    | ^
+  6 |
+=====================================output=====================================
+thisWontBeFormatted  ( 1  ,3)
+
+    thisWillBeFormatted(2, 3)<|>;
+
+    thisWontBeFormatted  (2, 90  ,)
+
+================================================================================
+`;

tests/format/js/cursor/range-5.js

@@ -0,0 +1 @@
+const myVar = <<<PRETTIER_RANGE_START>>>aFunction<|><<<PRETTIER_RANGE_END>>>

tests/format/js/cursor/range-6.js

@@ -0,0 +1 @@
+const myVar = <<<PRETTIER_RANGE_START>>>aFunction;<|><<<PRETTIER_RANGE_END>>>

tests/format/js/cursor/range-7.js

@@ -0,0 +1 @@
+const myVar = <<<PRETTIER_RANGE_START>>>aFunction<|>;<<<PRETTIER_RANGE_END>>>

tests/format/js/cursor/range-8.js

@@ -0,0 +1,5 @@
+thisWontBeFormatted  ( 1  ,3)
+<<<PRETTIER_RANGE_START>>>
+    thisWillBeFormatted    (2  ,3,   )<|>
+
+ <<<PRETTIER_RANGE_END>>>   thisWontBeFormatted  (2, 90  ,)