Jest json extend

Jest expect matchers for JSON strings with jsonpath supported. Inspirted by jest-json-matchers, further optimize and add jsonpath support.

New Matchers

.toBeJSON()

It will pass if input is a string and it can be deserialized by JSON.parse(). For example:

expect('{"hello":"world"}').toBeJSON(); // It will pass
expect('<span>Test</span>').toBeJSON(); // It will not pass

.toEqualJSON(jsonObject)

It will pass if input is a valid JSON string and its deserialized value is equal to the value passed to the matcher. It compares based on toEqual() matcher. For example:

expect('{"hello":"world"}').toEqualJSON({ hello: 'world' }); // It will pass
expect('{\n  "status": 400\n}').toEqualJSON({ status: 200 }); // It will not pass

.toMatcherJSON(jsonObject)

It will pass if input is a valid JSON string and its deserialized value contains the properties of the value passed to the matcher. It matches based on toMatchObject() matcher. For example:

expect('{"status":202,"body":null}').toMatchJSON({ status: 202 }); // It will pass
expect('{"day":14,"month":3}').toMatchJSON({ month: 12 });

expect.jsonContaining(jsonObject)

It will pass if input is a valid JSON string and its deserialized value contains the properties of the value passed to the matcher, It behaves like expect.objectContaining() matcher. For example:

// It will pass
expect({
  body: '{"message":"This is JSON"}',
}).toEqual({
  body: expect.jsonContaining({ message: 'This is JSON' }),
});
// It will not pass
expect({
  status: 200,
}).toEqual({
  body: expect.jsonContaining({ message: 'Not this one' }),
});

Setup

Add jest-json to your Jest config:

module.exports = {
  // ... other configurations
  setupFilesAfterEnv: ['jest-json-extend'],
};

Or load it explicitly

import jest-json-extend;

it('should pass', () => {
    expect('').not.toBeJSON()
})

Example with jsonpath

it('should pass', () => {
  const recevied = JSON.stringify({
    firstName: 'John',
    lastName: 'doe',
    age: 26,
    address: {
      streetAddress: 'naist street',
      city: 'Nara',
      postalCode: '630-0192',
    },
  });
  expect(recevied).toMatchJSON(
    address,
    '$.address[?(@property.match(/city/i))]^'
  );
});

License

MIT