Improve regex to replace root dir

Author: rubennorte

packages/babel-jest/src/index.ts

@@ -17,7 +17,7 @@ import {
   transformSync as babelTransform,
 } from '@babel/core';
 import chalk from 'chalk';
-import {escapeStrForRegex} from 'jest-regex-util';
+import {escapePathForRegex} from 'jest-regex-util';
 import slash from 'slash';
 
 const THIS_FILE = fs.readFileSync(__filename);
@@ -69,7 +69,7 @@ const createTransformer = (
   function getRootDirRegExp(rootDir: Config.Path): RegExp {
     if (!rootDirRegExpCache[rootDir]) {
       rootDirRegExpCache[rootDir] = new RegExp(
-        `^${escapeStrForRegex(rootDir)}(${escapeStrForRegex(path.sep)}|$)`,
+        `^${escapePathForRegex(rootDir)}(?=${escapePathForRegex(path.sep)}|$)`,
       );
     }
 
@@ -86,7 +86,7 @@ const createTransformer = (
     // babel options to relativize paths
     return JSON.stringify(babelOptions.options, (_key, value) => {
       if (typeof value === 'string') {
-        return value.replace(rootDirRegExp, '<rootDir>$1');
+        return value.replace(rootDirRegExp, '<rootDir>');
       }
       return value;
     });