expect(floatNumber).toBeNear(number, epsilon)

[Nolanus]

Compare a given value numerically to be in the range of number-epsilon and number+epsilon. Thus epsilon specifies the maximum tolerance the compared value is allowed to vary.

Example

expect(4.23223432434).toBeNear(4, 0.25); // success
expect(4.23223432434).toBeNear(4, 0.2); // failure

Implementation

Could internally use the "toBeWithinRange" matcher, but the above is much nicer to write if you're not targeting a specific range, but just a value and allow some wobbling.

[JamieMason]

Thank you for this, at what times would you use either this or Jasmine's toBeCloseTo please?

[Nolanus]

The second parameter of Jasmine's toBeCloseTo is non-linear. Especially when comparing integer values a lot of tweaking is required to get the expected "tolerance area":

expect(22).toBeNear(20, 2); // success
expect(22).toBeNear(20, 1); // failure
expect(22).toBeCloseTo(20, ??); // What to choose as "precision" parameter?

[JamieMason]

Thanks @Nolanus, do I understand correctly that

expect(22).toBeNear(20, 2);

is equivalent to

expect(22).toBeWithinRange(18, 22);

[Nolanus]

Hi @JamieMason,
that's correct.

Just realized my initial example was wrong, just fixed that.

[jacobwardio]

#68 adds the toBeNear() matcher.