propContains.md

layout	title	excerpt	groups	redirect_from	version_added
page-api	assert.propContains()	Check that an object contains certain properties.	assert	/assert/propContains/	2.18.0

propContains( actual, expected, message = "" )

Check that an object contains certain properties.

name	description
actual	Expression being tested
expected	Known comparison value
message (string)	Short description of the actual expression

The propContains assertion compares only the subset of properties in the expected object, and tests that these keys exist as own properties with strictly equal values.

This method is recursive and allows partial comparison of nested objects as well.

See also

• Use assert.propEqual() to compare all properties, considering extra properties as unexpected.
• Use assert.notPropContains() to test for the absence or inequality of properties.

Examples

QUnit.test('example', assert => {
  const result = {
    foo: 0,
    vehicle: {
      timeCircuits: 'on',
      fluxCapacitor: 'fluxing',
      engine: 'running'
    },
    quux: 1
  };

  assert.propContains(result, {
    foo: 0,
    vehicle: { fluxCapacitor: 'fluxing' }
  });

  function Point (x, y) {
    this.x = x;
    this.y = y;
  }

  assert.propContains(
    new Point(10, 20),
    { y: 20 }
  );

  assert.propContains(
    [ 'a', 'b' ],
    { 1: 'b' }
  );

  const nested = {
    north: [ /* ... */ ],
    east: new Point(10, 20),
    south: [ /* ... */ ],
    west: [ /* ... */ ]
  };

  assert.propContains(nested, { east: new Point(10, 20) });
  assert.propContains(nested, { east: { x: 10, y: 20 } });
  assert.propContains(nested, { east: { x: 10 } });
});