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This page describes a pre-release version of Jasmine (5.0.0-alpha.0). There may be additional changes, including breaking changes, before the final 5.0.0 release.
The current stable version of Jasmine is 5.5.

Namespace: matchers

matchers

Matchers that come with Jasmine out of the box.

Members

not :matchers

Invert the matcher following this expect

Type:
Since:
  • 1.3.0
Example
expect(something).not.toBe(true);

Methods

nothing()

expect nothing explicitly.

Since:
  • 2.8.0
Example
expect().nothing();

toBe(expected)

expect the actual value to be === to the expected value.

Parameters:
Name Type Description
expected Object

The expected value to compare against.
Since:
  • 1.3.0
Example
expect(thing).toBe(realThing);

toBeCloseTo(expected, precisionopt)

expect the actual value to be within a specified precision of the expected value.

Parameters:
Name Type Attributes Default Description
expected Object

The expected value to compare against.
precision Number <optional>
 2

The number of decimal points to check.
Since:
  • 1.3.0
Example
expect(number).toBeCloseTo(42.2, 3);

toBeDefined()

expect the actual value to be defined. (Not undefined)

Since:
  • 1.3.0
Example
expect(result).toBeDefined();

toBeFalse()

expect the actual value to be false.

Since:
  • 3.5.0
Example
expect(result).toBeFalse();

toBeFalsy()

expect the actual value to be falsy

Since:
  • 2.0.0
Example
expect(result).toBeFalsy();

toBeGreaterThan(expected)

expect the actual value to be greater than the expected value.

Parameters:
Name Type Description
expected Number

The value to compare against.
Since:
  • 2.0.0
Example
expect(result).toBeGreaterThan(3);

toBeGreaterThanOrEqual(expected)

expect the actual value to be greater than or equal to the expected value.

Parameters:
Name Type Description
expected Number

The expected value to compare against.
Since:
  • 2.0.0
Example
expect(result).toBeGreaterThanOrEqual(25);

toBeInstanceOf(expected)

expect the actual to be an instance of the expected class

Parameters:
Name Type Description
expected Object

The class or constructor function to check for
Since:
  • 3.5.0
Example
expect('foo').toBeInstanceOf(String);
expect(3).toBeInstanceOf(Number);
expect(new Error()).toBeInstanceOf(Error);

toBeLessThan(expected)

expect the actual value to be less than the expected value.

Parameters:
Name Type Description
expected Number

The expected value to compare against.
Since:
  • 2.0.0
Example
expect(result).toBeLessThan(0);

toBeLessThanOrEqual(expected)

expect the actual value to be less than or equal to the expected value.

Parameters:
Name Type Description
expected Number

The expected value to compare against.
Since:
  • 2.0.0
Example
expect(result).toBeLessThanOrEqual(123);

toBeNaN()

expect the actual value to be NaN (Not a Number).

Since:
  • 1.3.0
Example
expect(thing).toBeNaN();

toBeNegativeInfinity()

expect the actual value to be -Infinity (-infinity).

Since:
  • 2.6.0
Example
expect(thing).toBeNegativeInfinity();

toBeNull()

expect the actual value to be null.

Since:
  • 1.3.0
Example
expect(result).toBeNull();

toBePositiveInfinity()

expect the actual value to be Infinity (infinity).

Since:
  • 2.6.0
Example
expect(thing).toBePositiveInfinity();

toBeTrue()

expect the actual value to be true.

Since:
  • 3.5.0
Example
expect(result).toBeTrue();

toBeTruthy()

expect the actual value to be truthy.

Since:
  • 2.0.0
Example
expect(thing).toBeTruthy();

toBeUndefined()

expect the actual value to be undefined.

Since:
  • 1.3.0
Example
expect(result).toBeUndefined():

toContain(expected)

expect the actual value to contain a specific value.

Parameters:
Name Type Description
expected Object

The value to look for.
Since:
  • 2.0.0
Example
expect(array).toContain(anElement);
expect(string).toContain(substring);

toEqual(expected)

expect the actual value to be equal to the expected, using deep equality comparison.

Parameters:
Name Type Description
expected Object

Expected value
Since:
  • 1.3.0
Example
expect(bigObject).toEqual({"foo": ['bar', 'baz']});

toHaveBeenCalled()

expect the actual (a Spy) to have been called.

Since:
  • 1.3.0
Example
expect(mySpy).toHaveBeenCalled();
expect(mySpy).not.toHaveBeenCalled();

toHaveBeenCalledBefore(expected)

expect the actual value (a Spy) to have been called before another Spy.

Parameters:
Name Type Description
expected Spy

Spy that should have been called after the actual Spy.
Since:
  • 2.6.0
Example
expect(mySpy).toHaveBeenCalledBefore(otherSpy);

toHaveBeenCalledOnceWith()

expect the actual (a Spy) to have been called exactly once, and exactly with the particular arguments.

Parameters:
Type Attributes Description
Object <repeatable>

The arguments to look for
Since:
  • 3.6.0
Example
expect(mySpy).toHaveBeenCalledOnceWith('foo', 'bar', 2);

toHaveBeenCalledTimes(expected)

expect the actual (a Spy) to have been called the specified number of times.

Parameters:
Name Type Description
expected Number

The number of invocations to look for.
Since:
  • 2.4.0
Example
expect(mySpy).toHaveBeenCalledTimes(3);

toHaveBeenCalledWith()

expect the actual (a Spy) to have been called with particular arguments at least once.

Parameters:
Type Attributes Description
Object <repeatable>

The arguments to look for
Since:
  • 1.3.0
Example
expect(mySpy).toHaveBeenCalledWith('foo', 'bar', 2);

toHaveClass(expected)

expect the actual value to be a DOM element that has the expected class

Parameters:
Name Type Description
expected Object

The class name to test for
Since:
  • 3.0.0
Example
const el = document.createElement('div');
el.className = 'foo bar baz';
expect(el).toHaveClass('bar');

toHaveSize(expected)

expect the actual size to be equal to the expected, using array-like length or object keys size.

Parameters:
Name Type Description
expected Object

Expected size
Since:
  • 3.6.0
Example
array = [1,2];
expect(array).toHaveSize(2);

toHaveSpyInteractions()

expect the actual (a SpyObj) spies to have been called.

Since:
  • 4.1.0
Example
expect(mySpyObj).toHaveSpyInteractions();
expect(mySpyObj).not.toHaveSpyInteractions();

toMatch(expected)

expect the actual value to match a regular expression

Parameters:
Name Type Description
expected RegExp | String

Value to look for in the string.
Since:
  • 1.3.0
Example
expect("my string").toMatch(/string$/);
expect("other string").toMatch("her");

toThrow(expectedopt)

expect a function to throw something.

Parameters:
Name Type Attributes Description
expected Object <optional>

Value that should be thrown. If not provided, simply the fact that something was thrown will be checked.
Since:
  • 2.0.0
Example
expect(function() { return 'things'; }).toThrow('foo');
expect(function() { return 'stuff'; }).toThrow();

toThrowError(expectedopt, messageopt)

expect a function to throw an Error.

Parameters:
Name Type Attributes Description
expected Error <optional>

Error constructor the object that was thrown needs to be an instance of. If not provided, Error will be used.
message RegExp | String <optional>

The message that should be set on the thrown Error
Since:
  • 2.0.0
Example
expect(function() { return 'things'; }).toThrowError(MyCustomError, 'message');
expect(function() { return 'things'; }).toThrowError(MyCustomError, /bar/);
expect(function() { return 'stuff'; }).toThrowError(MyCustomError);
expect(function() { return 'other'; }).toThrowError(/foo/);
expect(function() { return 'other'; }).toThrowError();

toThrowMatching(predicate)

expect a function to throw something matching a predicate.

Parameters:
Name Type Description
predicate function

A function that takes the thrown exception as its parameter and returns true if it matches.
Since:
  • 3.0.0
Example
expect(function() { throw new Error('nope'); }).toThrowMatching(function(thrown) { return thrown.message === 'nope'; });

withContext(message) → {matchers}

Add some context for an expect

Parameters:
Name Type Description
message String

Additional context to show when the matcher fails
Since:
  • 3.3.0
Returns:
Type
matchers
This documentation is open source. Contributions are appreciated. Jasmine