From a00d31e1a4f6db1e16fb7a6f48496fcfb430544d Mon Sep 17 00:00:00 2001
From: Or Rosenblatt <orr001@gmail.com>
Date: Sat, 9 Jul 2022 00:30:26 -0400
Subject: [PATCH] Support `.lintstagedrc` (#13081)

* Test `.lintstagedrc` JSON and YML formatting (TDD)

* Support `.lintstagedrc` formatting

* Update spell checking for `.lintstagedrc`

* Update changelog

* Update changelog
---
 changelog_unreleased/cli/13081.md             |  3 +++
 cspell.json                                   |  2 ++
 src/language-yaml/embed.js                    |  4 +--
 src/language-yaml/index.js                    |  1 +
 .../__snapshots__/support-info.js.snap        |  3 ++-
 .../__tests__/with-parser-inference.js        | 25 +++++++++++++++++++
 6 files changed, 35 insertions(+), 3 deletions(-)
 create mode 100644 changelog_unreleased/cli/13081.md

diff --git a/changelog_unreleased/cli/13081.md b/changelog_unreleased/cli/13081.md
new file mode 100644
index 000000000..67acee028
--- /dev/null
+++ b/changelog_unreleased/cli/13081.md
@@ -0,0 +1,3 @@
+#### Infer parser for `.lintstagedrc` (#13081 by @OrRosenblatt)
+
+A `.lintstagedrc` file (without extension) is handled using `json` and `yaml` parsers.
diff --git a/cspell.json b/cspell.json
index 37f04c11c..8bd613b15 100644
--- a/cspell.json
+++ b/cspell.json
@@ -184,6 +184,8 @@
         "linearize",
         "linebreak",
         "linebreaks",
+        "lintstaged",
+        "lintstagedrc",
         "literalline",
         "loglevel",
         "lowercased",
diff --git a/src/language-yaml/embed.js b/src/language-yaml/embed.js
index cc3e0722c..244eb07a2 100644
--- a/src/language-yaml/embed.js
+++ b/src/language-yaml/embed.js
@@ -3,11 +3,11 @@
 function embed(path, print, textToDoc, options) {
   const node = path.getValue();
 
-  // Try to format `.prettierrc` and `.stylelintrc` as `json` first
+  // Try to format `.prettierrc`, `.stylelintrc`, and `.lintstagedrc` as `json` first
   if (
     node.type === "root" &&
     options.filepath &&
-    /(?:[/\\]|^)\.(?:prettier|stylelint)rc$/.test(options.filepath)
+    /(?:[/\\]|^)\.(?:prettier|stylelint|lintstaged)rc$/.test(options.filepath)
   ) {
     return textToDoc(options.originalText, { ...options, parser: "json" });
   }
diff --git a/src/language-yaml/index.js b/src/language-yaml/index.js
index 600ed4193..0a6815457 100644
--- a/src/language-yaml/index.js
+++ b/src/language-yaml/index.js
@@ -15,6 +15,7 @@ const languages = [
       ...data.filenames.filter((filename) => filename !== "yarn.lock"),
       ".prettierrc",
       ".stylelintrc",
+      ".lintstagedrc",
     ],
   })),
 ];
diff --git a/tests/integration/__tests__/__snapshots__/support-info.js.snap b/tests/integration/__tests__/__snapshots__/support-info.js.snap
index 8e6f7d9e0..fa53d0982 100644
--- a/tests/integration/__tests__/__snapshots__/support-info.js.snap
+++ b/tests/integration/__tests__/__snapshots__/support-info.js.snap
@@ -774,7 +774,8 @@ exports[`CLI --support-info (stdout) 1`] = `
         "CITATION.cff",
         "glide.lock",
         ".prettierrc",
-        ".stylelintrc"
+        ".stylelintrc",
+        ".lintstagedrc"
       ],
       "linguistLanguageId": 407,
       "name": "YAML",
diff --git a/tests/integration/__tests__/with-parser-inference.js b/tests/integration/__tests__/with-parser-inference.js
index 2e5d64527..f503eef40 100644
--- a/tests/integration/__tests__/with-parser-inference.js
+++ b/tests/integration/__tests__/with-parser-inference.js
@@ -70,4 +70,29 @@ describe("infers parser from filename", () => {
       ` + "\n"
     );
   });
+
+  test("json from .lintstagedrc", () => {
+    expect(
+      prettier.format("  {  '*':   'your-cmd'  }  ", {
+        filepath: "/path/to/.lintstagedrc",
+      })
+    ).toBe('{ "*": "your-cmd" }\n');
+  });
+
+  test("yaml from .lintstagedrc", () => {
+    expect(
+      prettier.format(
+        /* indent */ `
+          '*':
+                 - your-cmd
+        `,
+        { filepath: "/path/to/.lintstagedrc" }
+      )
+    ).toBe(
+      outdent`
+        "*":
+          - your-cmd
+      ` + "\n"
+    );
+  });
 });