See the example in the Recursive custom equality testers section for more details. If you use this function, pass through the custom testers your tester is given so further equality checks equals applies can also use custom testers the test author may have configured. It optionally takes a list of custom equality testers to apply to the deep equality checks. This is a deep-equality function that will return true if two objects have the same values (recursively). These helper functions and properties can be found on this inside a custom tester: this.equals(a, b, customTesters?) a class instance with fields a and b will not equal a literal object with fields a and b.Ĭustom testers are functions that return either the result ( true or false) of comparing the equality of the two given arguments or undefined if the tester does not handle the given objects and wants to delegate equality to other testers (for example, the builtin equality testers).Ĭustom testers are called with 3 arguments: the two objects to compare and the array of custom testers (used for recursive testers, see the section below). undefined items are taken into account, e.g.Object containing house features to be testedĪmenities : ,

You might want to check that drink gets called for 'lemon', but not for 'octopus', because 'octopus' flavour is really weird and why would anything be octopus-flavoured? You can do that with this test suite: toEqual uses.įor example, let's say you have a drinkAll(drink, flavour) function that takes a drink function and applies it to all available beverages. The arguments are checked with the same algorithm that. toHaveBeenCalledWith to ensure that a mock function was called with specific arguments. rewrite expect(received).not.toBe(expected) as expect(Object.is(received, expected)).toBe(false).rewrite expect(received).toBe(expected) as expect(Object.is(received, expected)).toBe(true).For example, to assert whether or not elements are the same instance: If differences between properties do not help you to understand why a test fails, especially if the report is large, then you might move the comparison into the expect function. toBe matcher checks referential identity, it reports a deep comparison of values if the assertion fails. For example, due to rounding, in JavaScript 0.2 + 0.1 is not strictly equal to 0.3. Here's how you would test that:ĭon't use. Let's say you have a method bestLaCroixFlavor() which is supposed to return the string 'grapefruit'. It's easier to understand this with an example. Instead, you will use expect along with a 'matcher' function to assert something about a value. The expect function is used every time you want to test a value. expect.addSnapshotSerializer(serializer).toThrowErrorMatchingInlineSnapshot(inlineSnapshot) toMatchInlineSnapshot(propertyMatchers?, inlineSnapshot) toMatchSnapshot(propertyMatchers?, hint?) toHaveBeenNthCalledWith(nthCall, arg1, arg2. Since Duration values are not comparable, the result of applying a comparison operator between two Duration values is null. If the type, point in time, offset, and time zone name are all equal, then the values are equal, and any difference in order is impossible to observe.ĭuration values cannot be compared, since the length of a day, month or year is not known without knowing which day, month or year it is. If two instant values represent the same point in time, and have the same time zone offset, but a different named time zone (this is possible for DateTime only, since Time only has an offset), these values are not considered equal, and ordered by the time zone identifier, alphabetically, as its third ordering component. This has the effect that times that represent the same point in time will be ordered with the time with the earliest local time first. Instant values that occur at the same point in time - but that have a different time zone - are not considered equal, and must therefore be ordered in some predictable way.Ĭypher prescribes that, after the primary order of point in time, instant values be ordered by effective time zone offset, from west (negative offset from UTC) to east (positive offset from UTC).

Temporal instant values are comparable within the same type.Īn instant is considered less than another instant if it occurs before that instant in time, and it is considered greater than if it occurs after.

Deprecations, additions, and compatibility.

Property, structural, and constructed values.

Javascript does not equal or less than