Use flag validation

src/cli/constant.js

@@ -77,10 +77,20 @@ const options = {
     type: "boolean",
   },
   "cache-strategy": {
+    choices: [
+      {
+        description: "Use the file metadata such as timestamps as cache keys",
+        value: "metadata",
+      },
+      {
+        description: "Use the file content as cache keys",
+        value: "content",
+      },
+    ],
     default: "metadata",
     describe:
       "Strategy for the cache to use for detecting changed files. Can be either `metadata` or `content`. ",
-    type: "string",
+    type: "choice",
   },
   check: {
     alias: "c",

src/cli/format-results-cache.js

@@ -38,32 +38,12 @@ function getMetadataFromFileDescriptor(fileDescriptor) {
   return fileDescriptor.meta;
 }
 
-const cacheStrategies = ["metadata", "content"];
-const cacheStrategiesSet = new Set(cacheStrategies);
-
-/**
- * @typedef {"metadata" | "content"} CacheStrategy
- *
- * @param {string} value
- * @returns {value is CacheStrategy}
- */
-function isValidCacheStrategy(value) {
-  return cacheStrategiesSet.has(value);
-}
-
 class FormatResultsCache {
   /**
    * @param {string} cacheFileLocation The path of cache file location. (default: `node_modules/.cache/prettier/prettier-cache`)
    * @param {string} cacheStrategy
    */
   constructor(cacheFileLocation, cacheStrategy) {
-    if (!isValidCacheStrategy(cacheStrategy)) {
-      const errorMessage = `Cache strategy must be one of: ${cacheStrategies
-        .map((strategy) => `"${strategy}"`)
-        .join(", ")}`;
-      throw new Error(errorMessage);
-    }
-
     const useChecksum = cacheStrategy === "content";
 
     this.cacheFileLocation = cacheFileLocation;

src/cli/format.js

@@ -301,15 +301,10 @@ async function formatFiles(context) {
   let formatResultsCache;
   const cacheFilePath = findCacheFile();
   if (context.argv.cache) {
-    try {
-      formatResultsCache = new FormatResultsCache(
-        cacheFilePath,
-        context.argv.cacheStrategy
-      );
-    } catch (error) {
-      context.logger.error(error.message);
-      process.exit(2);
-    }
+    formatResultsCache = new FormatResultsCache(
+      cacheFilePath,
+      context.argv.cacheStrategy
+    );
   } else {
     const stat = await statSafe(cacheFilePath);
     if (stat) {

tests/integration/__tests__/cache.js

@@ -40,7 +40,7 @@ describe("--cache option", () => {
       ".",
     ]);
     expect(stripAnsi(stderr.trim())).toBe(
-      '[error] Cache strategy must be one of: "metadata", "content"'
+      '[error] Invalid --cache-strategy value. Expected "content" or "metadata", but received "invalid".'
     );
   });