Nock

Repeating, Persisting, and Optional Interceptors ​

By default, an interceptor matches one request. Choose an exact repeat count, persist it across requests, or mark it optional when the request may not happen.

Repeat a Mock ​

Use .times(n) to repeat the same response an exact number of times:

js
const scope = nock('http://example.test')
  .get('/resource')
  .times(2)
  .reply(200, 'ok')

await fetch('http://example.test/resource')
await fetch('http://example.test/resource')
scope.done()

The .once(), .twice(), and .thrice() methods are shorthand for .times(1), .times(2), and .times(3):

js
nock('http://example.test').get('/one').once().reply(200)
nock('http://example.test').get('/two').twice().reply(200)
nock('http://example.test').get('/three').thrice().reply(200)

Once the configured number of requests is matched, the interceptor is consumed. A further unmatched request to the mocked origin receives a 501 response with code ERR_NOCK_NO_MATCH.

Persist Across Requests ​

Call .persist() on a scope to keep its interceptors active for repeated requests:

js
const scope = nock('http://example.test')
  .persist()
  .get('/health')
  .reply(200, 'ok')

await fetch('http://example.test/health')
await fetch('http://example.test/health')
scope.done()

A persisted scope is considered done after its first matching request. Call .persist(false) to stop persisting; use nock.cleanAll() to remove all interceptors, including persisted ones.

Make a Mock Optional ​

Use .optionally() when a request may or may not occur. An unconsumed optional interceptor does not appear in pendingMocks() and does not prevent scope.isDone() or scope.done() from succeeding:

js
const scope = nock('http://example.test')
  .get('/optional')
  .optionally()
  .reply(200, 'ok')

scope.done()

Pass a boolean to toggle optional behavior dynamically:

js
const addOptionalMock = optional =>
  nock('http://example.test')
    .get('/conditional')
    .optionally(optional)
    .reply(200)

addOptionalMock(true)
addOptionalMock(false)

For pending and active interceptor inspection, see Expectations.