From e9867a73532d7235cfc57210f0f59bdcd4967f5e Mon Sep 17 00:00:00 2001
From: Daniel <Daniel.Rosenwasser@microsoft.com>
Date: Mon, 11 May 2020 22:14:45 +0000
Subject: [PATCH] Add and use the 'intersperse' helper function.

---
 src/compiler/core.ts  | 16 ++++++++++++++++
 src/services/jsDoc.ts | 12 +++---------
 2 files changed, 19 insertions(+), 9 deletions(-)

diff --git a/src/compiler/core.ts b/src/compiler/core.ts
index 2841b80aedf..63e293f2e8f 100644
--- a/src/compiler/core.ts
+++ b/src/compiler/core.ts
@@ -129,6 +129,22 @@ namespace ts {
         return map;
     }
 
+    /**
+     * Creates a new array with `element` interspersed in between each element of `input`
+     * if there is more than 1 value in `input`. Otherwise, returns the existing array.
+     */
+    export function intersperse<T>(input: T[], element: T): T[] {
+        if (input.length <= 1) {
+            return input;
+        }
+        const result: T[] = [];
+        for (let i = 0, n = input.length; i < n; i++) {
+            if (i) result.push(element);
+            result.push(input[i]);
+        }
+        return result;
+    }
+
     /**
      * Iterates through `array` by index and performs the callback on each element of array until the callback
      * returns a falsey value, then returns false.
diff --git a/src/services/jsDoc.ts b/src/services/jsDoc.ts
index 2616aea3144..3115109572a 100644
--- a/src/services/jsDoc.ts
+++ b/src/services/jsDoc.ts
@@ -89,20 +89,14 @@ namespace ts.JsDoc {
         // Eg. const a: Array<string> | Array<number>; a.length
         // The property length will have two declarations of property length coming
         // from Array<T> - Array<string> and Array<number>
-        const documentationComment: SymbolDisplayPart[] = [];
+        const documentationComment: string[] = [];
         forEachUnique(declarations, declaration => {
             for (const { comment } of getCommentHavingNodes(declaration)) {
                 if (comment === undefined) continue;
-                const commentTextPart = textPart(comment);
-                if (!contains(documentationComment, commentTextPart)) {
-                    if (documentationComment.length) {
-                        documentationComment.push(lineBreakPart());
-                    }
-                    documentationComment.push(commentTextPart);
-                }
+                pushIfUnique(documentationComment, comment);
             }
         });
-        return documentationComment;
+        return intersperse(map(documentationComment, textPart), lineBreakPart());
     }
 
     function getCommentHavingNodes(declaration: Declaration): readonly (JSDoc | JSDocTag)[] {