fix: prevent maintaining RegExp state between calls

jestjs · Dec 10, 2019 · 08ca5b2 · 08ca5b2
1 parent 9ac2dcd
commit 08ca5b2
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Showing 2 changed files with 8 additions and 1 deletion.
diff --git a/packages/expect/src/__tests__/matchers.test.js b/packages/expect/src/__tests__/matchers.test.js
@@ -1615,6 +1615,13 @@ describe('.toMatch()', () => {
   it('escapes strings properly', () => {
     jestExpect('this?: throws').toMatch('this?: throws');
   });
+
+  it('does not maintain RegExp state between calls', () => {
+    const regex = /[f]\d+/gi;
+    jestExpect('f123').toMatch(regex);
+    jestExpect('F456').toMatch(regex);
+    jestExpect(regex.lastIndex).toBe(0);
+  });
 });
 
 describe('.toHaveLength', () => {

diff --git a/packages/expect/src/matchers.ts b/packages/expect/src/matchers.ts
@@ -835,7 +835,7 @@ const matchers: MatchersObject = {
     const pass =
       typeof expected === 'string'
         ? received.includes(expected)
-        : expected.test(received);
+        : new RegExp(expected).test(received);
 
     const message = pass
       ? () =>