feat(file): new implementation

Autofix, fix now!

Author: HigherOrderLogic

src/generators/file.ts

@@ -10,22 +10,28 @@ export const file = defineGenerator({
     const fullPath = resolvePath(args.src, { url, dir: config.dir });
     let contents = await readFile(fullPath, "utf8");
 
-    if (args.fromLine) {
-      if (args.fromLine < 0) {
-        throw new Error("line index can not be smaller than 1");
-      }
-      if (!args.toLine) {
-        throw new Error("fromLine exists but toLine is not defined");
+    if (args.lines) {
+      if (!/^(\d+)?:(\d+)?$/.test(args.lines)) {
+        throw new Error("invalid lines format");
       }
 
+      const [_startLine, _endLine] = args.lines.split(":");
+
       const lines = contents.split("\n");
-      if (args.toLine > lines.length) {
+
+      const startLine = _startLine === "" ? 0 : Number(_startLine);
+      const endLine = _endLine === "" ? lines.length : Number(_endLine);
+
+      if (startLine < 1) {
+        throw new Error("first line's index can not be smaller than 1");
+      }
+      if (endLine > lines.length) {
         throw new Error(
-          `line ${args.toLine} exceeds the total line number of the file`,
+          `line ${endLine} was specified while file ${fullPath} has only ${lines.length} lines`,
         );
       }
 
-      contents = lines.slice(args.fromLine - 1, args.toLine - 1).join("\n");
+      contents = lines.slice(startLine - 1, endLine - 1).join("\n");
     }
 
     if (args.code) {

test/fixture/OUTPUT.md

@@ -191,6 +191,8 @@ Programming can be hard. But fear not! With the power of copy-paste, you can con
 
 When your code doesn't work, don't blame yourself. It's clearly the compiler's fault for not understanding your genius. Remember, the more error messages you get, the closer you are to becoming a programming master.
 
+Why waste time solving problems when someone else has already done it for you? Stack Overflow is your best friend, your mentor, and your savior. Just make sure to upvote the answers that save your bacon.
+
 <!-- /automd -->
 
 ## `contributors`