Keep an own-line comment before a satisfies or as type on its own line - #19939

Is this the same as hasLeadingOwnLineComment?

Please answer directly under this comment.

Almost, but not quite. The difference is CommentCheckFlags.Line.

hasLeadingOwnLineComment matches any leading comment whose end is followed by a newline, so it also catches a block comment that opens on the operator's line and closes on a later one. I tried swapping it in:

1 as /*
  ...
*/
Foo;

currently prints as 1 as /* with Foo; back at column 0, and with hasLeadingOwnLineComment it becomes

1 as
  /*
  ...
  */
  Foo;

which fails tests/format/typescript/as/comments. Inline block comments like 1 as /* c */ Foo are unaffected either way, since there is no newline after them.

So it is a behaviour change rather than a refactor. If you would rather multiline block comments broke that way too, I am happy to drop the flag and update those snapshots, it does simplify this to a single existing helper. I kept it narrow because the change was about line comments.

The change to

1 as
  /*
  ...
  */
  Foo;

is expected. And I think it will fix the alignment issue cases that the comment is "indentable".

Done, switched to hasLeadingOwnLineComment and updated the as/comments snapshot to the shape you quoted.

That drops the local hasComment call and the hasNewline and locEnd imports with it, so this file now uses the existing helper rather than its own variant.

Checked the four shapes are stable across two passes: the multiline block comment, a line comment on its own line, an inline 1 as /* c */ Foo, and a union with a comment. The inline one is untouched, since there is no newline after it. Rest of the suite is unchanged against this branch, same 17 pre-existing failures before and after.

The union check is still here rather than in shouldIndentUnionType, per the other thread.

Add a test for "indentable" comment, can be a jsdoc.

Please also add a changelog for it. We can add another changelog entry at ‎changelog_unreleased/typescript/19939-2.md‎

I think we should include union type here, but exclude in shouldIndentUnionType?

I tried that and it regresses the long-line cases.

Adding (key === "typeAnnotation" && isBinaryCastExpression(parent)) to shouldIndentUnionType and dropping the union check here breaks as/break-after-keyword:

-const firstItem2 = ______________.items.find((item) => item.type === "item") as
-  string | number;
+const firstItem2 = ______________.items.find(
+  (item) => item.type === "item",
+) as string | number;

and worse on the one that already has a comment:

) as | a_union_will_break // comments

Three suites fail that way, as, as/break-after-keyword and flow/as-satisfies-expression. The indent after as is doing real work for line breaking, so removing it there is not free.

Unless you meant excluding it only when the type carries an own-line comment, which would keep the breaking behaviour and still move the knowledge into shouldIndentUnionType. I can try that shape if it is closer to what you had in mind.

This comment is meaningless, let's dro.

All three done.

Comment dropped. The jsdoc case is in as/comments, and it does show the alignment you predicted:

1 as
  /**
   * jsdoc
   */
  Foo;

against stable, which leaves it hanging off the operator:

1 as /**
 * jsdoc
 */
Foo;

Changelog added at changelog_unreleased/typescript/19939-2.md with that pair as the before and after.

Stop saying "All three done.", just reply comments one by one. There is no context for "three".

Understood, one reply per thread from here.

Point out it's misaligned before in the title.

Retitled to "Fix misaligned block comment before a satisfies or as type", so the heading says what was wrong rather than what it does now.

Use

const foo = {
  bar: 1,
} as
  // Comment
  Record<string, number>;

Swapped in, 9626796.

That shape shows the instability better than mine did. Stable prints } as // Comment on the first pass, then moves the comment to the end of the line on the second, so the changelog now has both stable outputs. I ran them rather than writing them out.