Stop retrying when fetch throws ERR_UNESCAPED_CHARACTERS error

index.js

@@ -55,8 +55,12 @@ function setup(fetch) {
             return res;
           }
         } catch (err) {
-          const isRetry = attempt <= retryOpts.retries;
-          debug(`${method} ${url} error (${err.status}). ${isRetry ? 'retrying' : ''}`, err);
+          const isClientError = err && err.code === 'ERR_UNESCAPED_CHARACTERS';
+          const isRetry = !isClientError && attempt <= retryOpts.retries;
+          debug(`${method} ${url} error (status = ${err.status}). ${isRetry ? 'retrying' : ''}`, err);
+          if (isClientError) {
+            return bail(err);
+          }
           throw err;
         }
       }, retryOpts);

test.js

@@ -1,3 +1,4 @@
+const assert = require('assert');
 const {createServer} =  require('http');
 const setup = require('./index');
 
@@ -145,3 +146,20 @@ test('stops retrying when the Retry-After header exceeds the maxRetryAfter optio
     server.on('error', reject);
   });
 });
+
+test('stops retrying when fetch throws `ERR_UNESCAPED_CHARACTERS` error', async () => {
+  const opts = {
+    onRetry: jest.fn(),
+  }
+
+  let err;
+  try {
+    await retryFetch(`http://127.0.0.1/\u0019`, opts);
+  } catch (_err) {
+    err = _err;
+  }
+
+  assert(err);
+  assert.equal(err.code, 'ERR_UNESCAPED_CHARACTERS');
+  assert.equal(opts.onRetry.mock.calls.length, 0);
+});