fix(intercept): handle global flags during regexp matching

When matching via a regexp instance, consistently test the entire target
string.
Sets the `lastIndex` to zero for cases where the `global` flag is set
and the
regexp instance has been tested previously.

fixes: #2134

lib/common.js

@@ -416,9 +416,12 @@ function matchStringOrRegexp(target, pattern) {
   const targetStr =
     target === undefined || target === null ? '' : String(target)
 
-  return pattern instanceof RegExp
-    ? pattern.test(targetStr)
-    : targetStr === String(pattern)
+  if (pattern instanceof RegExp) {
+    // if the regexp happens to have a global flag, we want to ensure we test the entire target
+    pattern.lastIndex = 0
+    return pattern.test(targetStr)
+  }
+  return targetStr === String(pattern)
 }
 
 /**

tests/test_intercept.js

@@ -884,6 +884,15 @@ test('match path using regexp', async t => {
   expect(body).to.equal('Match regex')
 })
 
+// https://github.com/nock/nock/issues/2134
+test('match path using regexp with global flag', async t => {
+  nock('http://example.test').get(/foo/g).reply(200, 'Match regex')
+
+  const { statusCode, body } = await got('http://example.test/foo/bar')
+  expect(statusCode).to.equal(200)
+  expect(body).to.equal('Match regex')
+})
+
 test('match path using function', async t => {
   const path = '/match/uri/function'
   const urlFunction = uri => uri === path