update replace behavior

Author: mshick

README.md

@@ -88,6 +88,8 @@ jobs:
 | update-only              | with     | Only update the comment if it already exists.                                                                                                                               | no       | false                              |
 | GITHUB_TOKEN             | env      | Valid GitHub token, can alternatively be defined in the env.                                                                                                                | no       |                                    |
 | preformatted             | with     | Treat message text as pre-formatted and place it in a codeblock                                                                                                             | no       |                                    |
+| find                     | with     | Patterns to find in an existing message and replace with either `replace` text or a resolved `message`. See [Find-and-Replace](#find-and-replace) for more detail.          | no       |                                    |
+| replace                  | with     | Strings to replace a found pattern with. Each new line is a new replacement, or if you only have one pattern, you can replace with a multiline string.                      | no       |                                    |
 
 ## Advanced Uses
 

__tests__/add-pr-comment.test.ts

@@ -97,10 +97,7 @@ const handlers = [
 const server = setupServer(...handlers)
 
 beforeAll(() => {
-  // vi.spyOn(console, 'log').mockImplementation(() => {})
-  // vi.spyOn(core, 'debug').mockImplementation(() => {})
-  // vi.spyOn(core, 'info').mockImplementation(() => {})
-  // vi.spyOn(core, 'warning').mockImplementation(() => {})
+  vi.spyOn(console, 'log').mockImplementation(() => {})
   server.listen({ onUnhandledRequest: 'error' })
 })
 afterAll(() => server.close())
@@ -517,6 +514,35 @@ describe('find and replace', () => {
     expect(core.setOutput).toHaveBeenCalledWith('comment-id', commentId)
   })
 
+  it('can multiple find and replace a single pattern with a multiline replacement', async () => {
+    inputs['find'] = 'hello'
+    inputs['message'] = 'h\ne\nl\nl\no'
+
+    const body = `<!-- add-pr-comment:${inputs['message-id']} -->\n\nhello\nworld`
+
+    const commentId = 123
+
+    const replyBody = [
+      {
+        id: commentId,
+        body,
+      },
+    ]
+
+    getIssueCommentsResponse = replyBody
+    postIssueCommentsResponse = {
+      id: commentId,
+    }
+
+    await run()
+
+    expect(`<!-- add-pr-comment:add-pr-comment -->\n\nh\ne\nl\nl\no\nworld`).toEqual(
+      messagePayload?.body,
+    )
+    expect(core.setOutput).toHaveBeenCalledWith('comment-updated', 'true')
+    expect(core.setOutput).toHaveBeenCalledWith('comment-id', commentId)
+  })
+
   it('can multiple find and replace text using a message-path', async () => {
     inputs['find'] = '<< FILE_CONTENTS >>'
     inputs['message-path'] = messagePath1Fixture

src/message.ts

@@ -107,7 +107,10 @@ export function findAndReplaceInMessage(
 
   for (const [i, f] of find.entries()) {
     const { regExp, modifiers } = splitFind(f)
-    message = message.replace(new RegExp(regExp, modifiers), replacement[i] ?? replacement[0])
+    message = message.replace(
+      new RegExp(regExp, modifiers),
+      replacement[i] ?? replacement.join('\n'),
+    )
   }
 
   return message