Validate JSON

prettier · Jul 16, 2022 · afcbd3c · afcbd3c
1 parent 2e228d9
commit afcbd3c
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Showing 3 changed files with 40 additions and 4 deletions.
diff --git a/src/cli/find-cache-file.js b/src/cli/find-cache-file.js
@@ -1,9 +1,10 @@
 "use strict";
 
+const fs = require("fs").promises;
 const os = require("os");
 const path = require("path");
 const findCacheDir = require("find-cache-dir");
-const { statSafe } = require("./utils.js");
+const { statSafe, isJson } = require("./utils.js");
 
 /**
  * Find default cache file (`./node_modules/.cache/prettier/.prettier-cache`) using https://github.com/avajs/find-cache-dir
@@ -21,9 +22,19 @@ async function findCacheFileFromOption(cacheLocation) {
   const cacheFile = path.join(cwd, normalized);
 
   const stat = await statSafe(cacheFile);
-  if (stat && stat.isDirectory()) {
-    throw new Error(`Resolved --cache-location '${cacheFile}' is a directory`);
+  if (stat) {
+    if (stat.isDirectory()) {
+      throw new Error(
+        `Resolved --cache-location '${cacheFile}' is a directory`
+      );
+    }
+
+    const data = await fs.readFile(cacheFile, "utf8");
+    if (!isJson(data)) {
+      throw new Error(`'${cacheFile}' isn't a valid JSON file`);
+    }
   }
+
   return cacheFile;
 }
 

diff --git a/src/cli/utils.js b/src/cli/utils.js
@@ -67,4 +67,17 @@ async function statSafe(filePath) {
   }
 }
 
-module.exports = { printToScreen, groupBy, pick, createHash, statSafe };
+/**
+ * @param {string} value
+ * @returns {boolean}
+ */
+function isJson(value) {
+  try {
+    JSON.parse(value);
+    return true;
+  } catch {
+    return false;
+  }
+}
+
+module.exports = { printToScreen, groupBy, pick, createHash, statSafe, isJson };
diff --git a/tests/integration/__tests__/cache.js b/tests/integration/__tests__/cache.js
@@ -407,6 +407,18 @@ describe("--cache option", () => {
       );
     });
 
+    it("throws error for invalid JSON file", async () => {
+      const { stderr } = await runPrettier(dir, [
+        "--cache",
+        "--cache-location",
+        "a.js",
+        ".",
+      ]);
+      expect(stripAnsi(stderr).trim()).toEqual(
+        expect.stringMatching(/\[error] '.+' isn't a valid JSON file/)
+      );
+    });
+
     describe("file", () => {
       it("creates the cache file at location specified by `--cache-location`", async () => {
         await expect(fs.stat(nonDefaultCacheFilePath)).rejects.toHaveProperty(