[handlebars] allow custom "else if"-like with block params (#13930)

changelog_unreleased/handlebars/13930.md

@@ -0,0 +1,42 @@
+#### Allow custom "else if"-like blocks with block params (#13930 by @jamescdavis)
+
+#13507 added support for custom block keywords used with `else`, but failed to allow block params. This updates printer-glimmer to allow block params with custom "else if"-like blocks.
+
+<!-- prettier-ignore -->
+```hbs
+{{! Input }}
+{#when isAtWork as |work|}}
+  Ship that
+  {{work}}!
+{{else when isReading as |book|}}
+  You can finish
+  {{book}}
+  eventually...
+{{else}}
+  Go to bed!
+{{/when}}
+
+{{! Prettier stable }}
+{{#when isAtWork as |work|}}
+  Ship that
+  {{work}}!
+{{else when isReading}}
+  You can finish
+  {{book}}
+  eventually...
+{{else}}
+  Go to bed!
+{{/when}}
+
+{{! Prettier main }}
+{#when isAtWork as |work|}}
+  Ship that
+  {{work}}!
+{{else when isReading as |book|}}
+  You can finish
+  {{book}}
+  eventually...
+{{else}}
+  Go to bed!
+{{/when}}
+```

src/language-handlebars/printer-glimmer.js

@@ -563,16 +563,28 @@ function printElseBlock(node, options) {
 }
 
 function printElseIfLikeBlock(path, print, ifLikeKeyword) {
+  const node = path.getValue();
+  let blockParams = [];
+
+  if (isNonEmptyArray(node.program.blockParams)) {
+    blockParams = [line, printBlockParams(node.program)];
+  }
+
   const parentNode = path.getParentNode(1);
 
-  return [
+  return group([
     printInverseBlockOpeningMustache(parentNode),
-    "else ",
-    ifLikeKeyword,
-    " ",
-    printParams(path, print),
+    indent(
+      group([
+        group(["else", line, ifLikeKeyword]),
+        line,
+        printParams(path, print),
+      ])
+    ),
+    indent(blockParams),
+    softline,
     printInverseBlockClosingMustache(parentNode),
-  ];
+  ]);
 }
 
 function printCloseBlock(path, print, options) {

tests/format/handlebars/block-statement/__snapshots__/jsfmt.spec.js.snap

@@ -274,6 +274,26 @@ printWidth: 80
   Another thing
 {{~/when~}}
 
+{{#when a as |b|}}
+  {{b}}
+{{else when c as |d|}}
+  {{d}}
+{{else when e as |f|}}
+  {{f}}
+{{else when g as |h|}}
+  {{h}}
+{{else}}
+  j
+{{/when}}
+
+{{#when abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrst as |b|}}
+  {{b}}
+{{else when abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnop as |d|}}
+  {{d}}
+{{else when abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz as |f|}}
+  {{f}}
+{{/when}}
+
 =====================================output=====================================
 <h1>
   {{#when isAtWork}}
@@ -381,6 +401,34 @@ printWidth: 80
 {{~else when anotherCondition~}}
   Another thing
 {{~/when~}}
+
+{{#when a as |b|}}
+  {{b}}
+{{else when c as |d|}}
+  {{d}}
+{{else when e as |f|}}
+  {{f}}
+{{else when g as |h|}}
+  {{h}}
+{{else}}
+  j
+{{/when}}
+
+{{#when
+  abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrst
+  as |b|
+}}
+  {{b}}
+{{else when abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnop
+  as |d|
+}}
+  {{d}}
+{{else when
+  abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz
+  as |f|
+}}
+  {{f}}
+{{/when}}
 ================================================================================
 `;
 

tests/format/handlebars/block-statement/custom-else.hbs

@@ -106,3 +106,23 @@
 {{~else when anotherCondition~}}
   Another thing
 {{~/when~}}
+
+{{#when a as |b|}}
+  {{b}}
+{{else when c as |d|}}
+  {{d}}
+{{else when e as |f|}}
+  {{f}}
+{{else when g as |h|}}
+  {{h}}
+{{else}}
+  j
+{{/when}}
+
+{{#when abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrst as |b|}}
+  {{b}}
+{{else when abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnop as |d|}}
+  {{d}}
+{{else when abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz as |f|}}
+  {{f}}
+{{/when}}