fix: restrict filename length & prevent overwriting files with dup. n…

…ames

Summary:
- File name (without the extension) is restricted to 40 chars
- If the file name already exists, a short hash based on the file
contents will be added to the file name

src/main.ts

@@ -1,6 +1,7 @@
 #!/usr/bin/env node
 
 import * as fs from "fs";
+import { createHash } from "crypto";
 import * as path from "path";
 import * as tmp from "tmp";
 import { promisify } from "util";
@@ -96,7 +97,24 @@ function convertNote(filePath: string, outputDir: string): boolean {
   var output = serialize(note);
 
   output.forEach(out => {
-    fs.writeFileSync(path.join(outputDir, out.fileName), out.content);
+    let outputPath = path.join(outputDir, out.fileName);
+    if (fs.existsSync(outputPath)) {
+      const ext = path.extname(outputPath)
+      const fileNameWithoutExt = out.fileName.replace(
+        new RegExp(ext + '$'),
+        ''
+      )
+      const fileHash = createHash('sha256')
+      fileHash.update(out.content)
+      const digest = fileHash
+        .digest("base64")
+        .replace(/[^A-Za-z0-9]/g, "")
+        .substring(0, 4);
+      const newFileName = `${fileNameWithoutExt}-${digest}${ext}`;
+      outputPath = path.join(outputDir, newFileName);
+    }
+
+    fs.writeFileSync(outputPath, out.content);
   });
 
   return output.length > 0;

src/serializer.ts

@@ -3,6 +3,8 @@ var uuidV4 = require("uuid/v4");
 import * as yaml from "js-yaml";
 import { Note } from "./types";
 
+const MAX_FILENAME_LENGTH = 40;
+
 interface SerializedNote {
   fileName: string;
   content: string | Buffer;
@@ -61,11 +63,11 @@ function generateFilename(note: Note) {
         else newStr += char;
       }
     }
-    return newStr;
+    return newStr.substring(0, MAX_FILENAME_LENGTH);
   }
   const firstLine = note.content.trim().split('\n')[0];
   return sanitizeString(
-    note.title || firstLine || note.date || uuidV4()) 
+    note.title || firstLine || note.date || uuidV4())
     + ".md";
 }