sourcemaps now map properly in prettified code

package.json

@@ -24,11 +24,13 @@
     "@babel/code-frame": "^7.26.2",
     "@codemirror/lang-javascript": "^6.2.2",
     "@types/babel__code-frame": "^7.0.6",
+    "@types/diff": "^6.0.0",
     "@types/json-stable-stringify": "^1.1.0",
     "@types/node": "^22.10.2",
     "@uiw/codemirror-theme-abcdef": "^4.23.7",
     "@uiw/react-codemirror": "^4.23.7",
     "commander": "^12.1.0",
+    "diff": "^7.0.0",
     "ignore": "^6.0.2",
     "index-to-position": "^1.0.0",
     "js-base64": "^3.7.7",

src/library-manager.ts

@@ -21,7 +21,7 @@ import stringify from "json-stringify-pretty-compact";
 import { init_global_context } from "./global-module";
 import { parse_dts } from "./parse-dts";
 
-const cookie = "rewrite-ts-021";
+const cookie = "rewrite-ts-022";
 
 type module_state =
   | { type: "initial" }

src/pprint.ts

@@ -8,6 +8,7 @@ import * as prettier_estree from "prettier/plugins/estree";
 import { SourceMapGenerator } from "source-map";
 import { Base64 } from "js-base64";
 import { assert } from "./assert";
+import * as Diff from "diff";
 
 type n = { val: string; src: source | false };
 type ns = n | ns[];
@@ -202,7 +203,9 @@ async function add_src_map(code: string, ls: n[], options: map_options): Promise
   });
   const map_string = srcmap.toString();
   const base64 = Base64.encode(map_string);
-  return `${code}\n//# sourceMappingURL=data:application/json;charset=utf-8;base64,${base64}\n`;
+  return (
+    `${code}\n` + `//# sourceMappingURL=data:application/json;charset=utf-8;base64,${base64}\n`
+  );
 }
 
 export async function pretty_print(code: string) {
@@ -223,12 +226,54 @@ type options = {
   map?: map_options;
 };
 
+type d = { added: boolean; removed: boolean; value: string };
+
+function remap(ls: n[], diffs: d[]): n[] {
+  const new_ls: n[] = [];
+  let i = 0,
+    j = 0;
+  while (i < diffs.length) {
+    const { added, removed, value } = diffs[i];
+    if (added) {
+      if (removed) {
+        throw new Error("invalid diff");
+      } else {
+        // new text added
+        new_ls.push({ src: false, val: value });
+      }
+    } else {
+      if (removed) {
+        /* nothing added but stuff removed */
+        let k = 0;
+        while (k < value.length) {
+          const item = ls[j];
+          k += item.val.length;
+          j += 1;
+        }
+        assert(k === value.length);
+      } else {
+        /* nothing added and nothing removed */
+        let k = 0;
+        while (k < value.length) {
+          const item = ls[j];
+          new_ls.push(item);
+          k += item.val.length;
+          j += 1;
+        }
+        assert(k === value.length);
+      }
+    }
+    i += 1;
+  }
+  assert(j === ls.length);
+  return new_ls;
+}
+
 export async function pprint(loc: Loc, options: options): Promise<string> {
   const ls = ns_flatten(loc_to_ns(loc));
   const code = ls.map((x) => x.val).join("");
-  return options.prettify
-    ? await pretty_print(code)
-    : options.map
-      ? add_src_map(code, ls, options.map)
-      : code;
+  const pretty = await pretty_print(code);
+  const diff = Diff.diffWordsWithSpace(code, pretty);
+  const pretty_ls = remap(ls, diff);
+  return options.map ? add_src_map(pretty, pretty_ls, options.map) : pretty;
 }

test-project/.rts/main.rts.json

@@ -1,6 +1,6 @@
 {
   "cid": "test-project/main.rts rewrite-ts-visualized 0.0.0",
-  "cookie": "rewrite-ts-021",
+  "cookie": "rewrite-ts-022",
   "imports": [
     {
       "pkg": {"name": "rewrite-ts-visualized", "version": "0.0.0"},

test-project/.rts/main.rts.ts

@@ -1,2 +1,7 @@
-import { type t_2 as t_2 , x_1 as x_3 , f_3 as f_4 } from "./mod.rts.ts" ; import { expect as expect_5 } from "vitest" ; export const y_1 : t_2 = ( x_3 + f_4 ) ; console . log ( expect_5 ) ; console . log ( y_1 ) ;
-//# sourceMappingURL=data:application/json;charset=utf-8;base64,eyJ2ZXJzaW9uIjozLCJzb3VyY2VzIjpbIi4uL21haW4ucnRzIiwiLi4vbW9kLnJ0cyJdLCJuYW1lcyI6WyJ5IiwidCIsIngiLCJmIiwiY29uc29sZSIsImxvZyIsImV4cGVjdCJdLCJtYXBwaW5ncyI6ImdJQUVBLE1BQU1BLElBQUMsRUFBRUMsSUFBRSxJQUFFQyxJQUFFLEVDR3lCQyxRREZ4Q0MsUUFBTyxFQUFDQyxJQUFHLEVBQUNDLFNBQU0sSUFDbEJGLFFBQU8sRUFBQ0MsSUFBRyxFQUFDTCxJQUFDIiwiZmlsZSI6Im1haW4ucnRzLnRzIn0=
+import { type t_2 as t_2, x_1 as x_3, f_3 as f_4 } from "./mod.rts.ts";
+import { expect as expect_5 } from "vitest";
+export const y_1: t_2 = x_3 + f_4;
+console.log(expect_5);
+console.log(y_1);
+
+//# sourceMappingURL=data:application/json;charset=utf-8;base64,eyJ2ZXJzaW9uIjozLCJzb3VyY2VzIjpbIi4uL21haW4ucnRzIiwiLi4vbW9kLnJ0cyJdLCJuYW1lcyI6WyJ5IiwidCIsIngiLCJmIiwiY29uc29sZSIsImxvZyIsImV4cGVjdCJdLCJtYXBwaW5ncyI6Ijs7T0FFQSxNQUFNQSxHQUFDLEVBQUVDLElBQUUsRUFBRUMsSUFBRSxFQ0d5QkM7QURGeENDLE9BQU8sQ0FBQ0MsR0FBRyxDQUFDQyxRQUFNO0FBQ2xCRixPQUFPLENBQUNDLEdBQUcsQ0FBQ0wsR0FBQyIsImZpbGUiOiJtYWluLnJ0cy50cyJ9

test-project/.rts/mod.rts.json

@@ -1,6 +1,6 @@
 {
   "cid": "test-project/mod.rts rewrite-ts-visualized 0.0.0",
-  "cookie": "rewrite-ts-021",
+  "cookie": "rewrite-ts-022",
   "imports": [],
   "exported_identifiers": {
     "x": [

test-project/.rts/mod.rts.ts

@@ -1,2 +1,5 @@
-export const x_1 = 12 ; export type t_2 = number ; export const f_3 = 13 ;
-//# sourceMappingURL=data:application/json;charset=utf-8;base64,eyJ2ZXJzaW9uIjozLCJzb3VyY2VzIjpbIi4uL21vZC5ydHMiXSwibmFtZXMiOlsieCIsInQiLCJmIl0sIm1hcHBpbmdzIjoiQUFBQSxPQUFPLE1BQU1BLElBQUUsRUFBRSxHQUFFLEVBQ25CLE9BQU8sS0FBS0MsSUFBRSxFQUFFLE9BQU0sU0FFdEIsTUFBTUMsSUFBRSxFQUFFIiwiZmlsZSI6Im1vZC5ydHMudHMifQ==
+export const x_1 = 12;
+export type t_2 = number;
+export const f_3 = 13;
+
+//# sourceMappingURL=data:application/json;charset=utf-8;base64,eyJ2ZXJzaW9uIjozLCJzb3VyY2VzIjpbIi4uL21vZC5ydHMiXSwibmFtZXMiOlsieCIsInQiLCJmIl0sIm1hcHBpbmdzIjoiQUFBQSxPQUFPLE1BQU1BLElBQUUsRUFBRSxFQUFFO0FBQ25CLE9BQU8sS0FBS0MsSUFBRSxFQUFFLE1BQU07T0FFdEIsTUFBTUMsSUFBRSxFQUFFIiwiZmlsZSI6Im1vZC5ydHMudHMifQ==

test-project/.rts/sourcemap1.test.rts.json

@@ -1,6 +1,6 @@
 {
   "cid": "test-project/sourcemap1.test.rts rewrite-ts-visualized 0.0.0",
-  "cookie": "rewrite-ts-021",
+  "cookie": "rewrite-ts-022",
   "imports": [
     {
       "pkg": {"name": "vitest", "version": "2.1.8"},

test-project/.rts/sourcemap1.test.rts.ts

@@ -1,2 +1,10 @@
-import { suite as suite_1 , test as test_2 , expect as expect_5 } from "vitest" ; suite_1 ( "source mapping for errors" , ( ( ) => { test_2 ( "simple error" , ( ( ) => { const err_3 = new Error ( "HERE" ) ; const trace_4 = ( ( err_3 . stack || "" ) ) . split ( "\n" ) ; expect_5 ( trace_4 [ 1 ] ) . toMatch ( /\/sourcemap1\.test\.rts:5:17$/ ) ; } ) ) ; } ) ) ;
-//# sourceMappingURL=data:application/json;charset=utf-8;base64,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
+import { suite as suite_1, test as test_2, expect as expect_5 } from "vitest";
+suite_1("source mapping for errors", () => {
+  test_2("simple error", () => {
+    const err_3 = new Error("HERE");
+    const trace_4 = (err_3.stack || "").split("\n");
+    expect_5(trace_4[1]).toMatch(/\/sourcemap1\.test\.rts:5:17$/);
+  });
+});
+
+//# sourceMappingURL=data:application/json;charset=utf-8;base64,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