Add prefix and suffix inputs to wrap comment body

Co-authored-by: marocchino <128431+marocchino@users.noreply.github.com>

README.md

@@ -112,6 +112,18 @@ with:
   path: path-to-comment-contents.txt
 ```
 
+### Wrap file output in a code block
+
+Use `prefix` and `suffix` to wrap the comment body with arbitrary text, such as triple backticks for a code block.
+
+````yaml
+uses: marocchino/sticky-pull-request-comment@v3
+with:
+  path: path-to-comment-contents.txt
+  prefix: "```"
+  suffix: "```"
+````
+
 ### Delete the previous comment and add a comment at the end
 
 ```yaml
@@ -222,6 +234,14 @@ For more detailed information about permissions, you can read from the link belo
 
 **Optional** Comment message
 
+### `prefix`
+
+**Optional** Text to prepend to the comment body (before `message` or `path` content). Useful for opening a code block with ` ``` `.
+
+### `suffix`
+
+**Optional** Text to append to the comment body (after `message` or `path` content). Useful for closing a code block with ` ``` `.
+
 ### `path`
 
 **Optional** Path to file containing comment message

__tests__/config.test.ts

@@ -210,4 +210,49 @@ describe("getBody", () => {
     expect(await config.getBody()).toBe("")
     expect(core.setFailed).toHaveBeenCalledWith("glob error")
   })
+
+  test("wraps message with prefix and suffix", async () => {
+    const {config, core} = await loadConfig()
+    vi.mocked(core.getInput).mockImplementation(name => {
+      if (name === "message") return "hello there"
+      if (name === "prefix") return "```"
+      if (name === "suffix") return "```"
+      return ""
+    })
+    expect(await config.getBody()).toBe("```\nhello there\n```")
+  })
+
+  test("wraps file content with prefix and suffix", async () => {
+    const {config, core} = await loadConfig()
+    vi.mocked(core.getMultilineInput).mockReturnValue(["__tests__/assets/result"])
+    vi.mocked(core.getInput).mockImplementation(name => {
+      if (name === "prefix") return "```"
+      if (name === "suffix") return "```"
+      return ""
+    })
+    mockGlobCreate.mockResolvedValue({
+      glob: vi.fn().mockResolvedValue([resolve("__tests__/assets/result")]),
+    })
+    expect(await config.getBody()).toBe("```\nhi there\n\n```")
+  })
+
+  test("applies only prefix when suffix is not provided", async () => {
+    const {config, core} = await loadConfig()
+    vi.mocked(core.getInput).mockImplementation(name => {
+      if (name === "message") return "hello there"
+      if (name === "prefix") return "```"
+      return ""
+    })
+    expect(await config.getBody()).toBe("```\nhello there")
+  })
+
+  test("applies only suffix when prefix is not provided", async () => {
+    const {config, core} = await loadConfig()
+    vi.mocked(core.getInput).mockImplementation(name => {
+      if (name === "message") return "hello there"
+      if (name === "suffix") return "```"
+      return ""
+    })
+    expect(await config.getBody()).toBe("hello there\n```")
+  })
 })

action.yml

@@ -54,6 +54,12 @@ inputs:
   message:
     description: "comment message"
     required: false
+  prefix:
+    description: "text to prepend to the message (e.g. ` ``` ` to open a code block)"
+    required: false
+  suffix:
+    description: "text to append to the message (e.g. ` ``` ` to close a code block)"
+    required: false
   path:
     description: "glob path to file(s) containing comment message"
     required: false

src/config.ts

@@ -50,13 +50,17 @@ export async function getBody(): Promise<string> {
   const followSymbolicLinks = core.getBooleanInput("follow_symbolic_links", {
     required: true,
   })
+  const prefixInput = core.getInput("prefix", {required: false})
+  const suffixInput = core.getInput("suffix", {required: false})
+
+  let body: string
   if (pathInput && pathInput.length > 0) {
     try {
       const globber = await create(pathInput.join("\n"), {
         followSymbolicLinks,
         matchDirectories: false,
       })
-      return (await globber.glob()).map(path => readFileSync(path, "utf-8")).join("\n")
+      body = (await globber.glob()).map(path => readFileSync(path, "utf-8")).join("\n")
     } catch (error) {
       if (error instanceof Error) {
         core.setFailed(error.message)
@@ -64,6 +68,16 @@ export async function getBody(): Promise<string> {
       return ""
     }
   } else {
-    return core.getInput("message", {required: false})
+    body = core.getInput("message", {required: false})
   }
+
+  if (prefixInput || suffixInput) {
+    const parts: string[] = []
+    if (prefixInput) parts.push(prefixInput)
+    parts.push(body)
+    if (suffixInput) parts.push(suffixInput)
+    return parts.join("\n")
+  }
+
+  return body
 }