fix(issue-3982): Glimmer printer now properly handles else-if blocks without else block … (#4256)

* fix(glimmer): Now properly handles else-if blocks without else block and block statements as root of else.

* run prettier on printer-glimmer.js

src/language-handlebars/printer-glimmer.js

@@ -96,11 +96,16 @@ function print(path, options, print) {
     }
     case "BlockStatement": {
       const pp = path.getParentNode(1);
-      const isElseIf = pp && pp.inverse && pp.inverse.body[0] === n;
+      const isElseIf =
+        pp &&
+        pp.inverse &&
+        pp.inverse.body[0] === n &&
+        pp.inverse.body[0].path.parts[0] === "if";
       const hasElseIf =
         n.inverse &&
         n.inverse.body[0] &&
-        n.inverse.body[0].type === "BlockStatement";
+        n.inverse.body[0].type === "BlockStatement" &&
+        n.inverse.body[0].path.parts[0] === "if";
       const indentElse = hasElseIf ? a => a : indent;
       if (n.inverse) {
         return concat([
@@ -114,6 +119,11 @@ function print(path, options, print) {
             : "",
           isElseIf ? "" : concat([hardline, printCloseBlock(path, print)])
         ]);
+      } else if (isElseIf) {
+        return concat([
+          concat(["{{else ", printPathParams(path, print), "}}"]),
+          indent(concat([hardline, path.call(print, "program")]))
+        ]);
       }
       /**
        * I want this boolean to be: if params are going to cause a break,

tests/html_glimmer/__snapshots__/jsfmt.spec.js.snap

@@ -321,7 +321,22 @@ exports[`else-if.hbs 1`] = `
     {{/if}}
   </div>
 </div>
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+{{#if a}}
+  b
+{{else}}
+  {{#each c as |d|}}
+    e
+  {{/each}}
+{{/if}}
+
+{{#if a}}
+  {{#if b}}
+    ab
+  {{else if c}}
+    ac
+  {{/if}}
+{{/if}}~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 {{#if a}}
   b
 {{else if c}}
@@ -371,6 +386,20 @@ exports[`else-if.hbs 1`] = `
     {{/if}}
   </div>
 </div>
+{{#if a}}
+  b
+{{else}}
+  {{#each c as |d|}}
+    e
+  {{/each}}
+{{/if}}
+{{#if a}}
+  {{#if b}}
+    ab
+  {{else if c}}
+    ac
+  {{/if}}
+{{/if}}
 `;
 
 exports[`literals.hbs 1`] = `

tests/html_glimmer/else-if.hbs

@@ -51,3 +51,19 @@
     {{/if}}
   </div>
 </div>
+
+{{#if a}}
+  b
+{{else}}
+  {{#each c as |d|}}
+    e
+  {{/each}}
+{{/if}}
+
+{{#if a}}
+  {{#if b}}
+    ab
+  {{else if c}}
+    ac
+  {{/if}}
+{{/if}}