Matchers can be passed as arguments to spy.calledOn, spy.calledWith, spy.returned and the corresponding sinon.assert functions as well as spy.withArgs. Matchers allow to be either more fuzzy or more specific about the expected value.

"test should assert fuzzy": function () {
    var book = {
        pages: 42,
        author: "cjno"
        id: {
          isbn10: "0596517742",
          isbn13: "978-0596517748"
        }
    };
    var spy = sinon.spy();

    spy(book);

    sinon.assert.calledWith(spy, sinon.match({ author: "cjno" }));
    sinon.assert.calledWith(spy, sinon.match.has("pages", 42));
    sinon.assert.calledWith(spy, sinon.match.has("id", sinon.match.has("isbn13", "978-0596517748")));
}

"test should stub method differently based on argument types": function () {
    var callback = sinon.stub();
    callback.withArgs(sinon.match.string).returns(true);
    callback.withArgs(sinon.match.number).throws("TypeError");

    callback("abc"); // Returns true
    callback(123); // Throws TypeError
}

Matchers API

sinon.match(number);

Requires the value to be == to the given number.

sinon.match(string);

Requires the value to be a string and have the expectation as a substring.

sinon.match(regexp);

Requires the value to be a string and match the given regular expression.

sinon.match(object);

Requires the value to be not null or undefined and have at least the same properties as expectation.

This supports nested matchers.

sinon.match(function)

See custom matchers.

sinon.match.any

Matches anything.

sinon.match.defined

Requires the value to be defined.

sinon.match.truthy

Requires the value to be truthy.

sinon.match.falsy

Requires the value to be falsy.

sinon.match.bool

Requires the value to be a Boolean

sinon.match.number

Requires the value to be a Number.

sinon.match.string

Requires the value to be a String.

sinon.match.object

Requires the value to be an Object.

sinon.match.func

Requires the value to be a Function.

sinon.match.array

Requires the value to be an Array.

sinon.match.array.deepEquals(arr)

Requires an Array to be deep equal another one.

sinon.match.array.startsWith(arr)

Requires an Array to start with the same values as another one.

sinon.match.array.endsWith(arr)

Requires an Array to end with the same values as another one.

sinon.match.array.contains(arr)

Requires an Array to contain each one of the values the given array has.

sinon.match.map

Requires the value to be a Map.

sinon.match.map.deepEquals(map)

Requires a Map to be deep equal another one.

sinon.match.map.contains(map)

Requires a Map to contain each one of the items the given map has.

sinon.match.set

Requires the value to be a Set.

sinon.match.set.deepEquals(set)

Requires a Set to be deep equal another one.

sinon.match.set.contains(set)

Requires a Set to contain each one of the items the given set has.

sinon.match.regexp

Requires the value to be a regular expression.

sinon.match.date

Requires the value to be a Date object.

sinon.match.symbol

Requires the value to be a Symbol.

sinon.match.in(array)

Requires the value to be in the array.

sinon.match.same(ref)

Requires the value to strictly equal ref.

sinon.match.typeOf(type)

Requires the value to be of the given type, where type can be one of "undefined", "null", "boolean", "number", "string", "object", "function", "array", "regexp", "date" or "symbol".

sinon.match.instanceOf(type)

Requires the value to be an instance of the given type.

sinon.match.has(property[, expectation])

Requires the value to define the given property.

The property might be inherited via the prototype chain. If the optional expectation is given, the value of the property is deeply compared with the expectation. The expectation can be another matcher.

sinon.match.hasOwn(property[, expectation])

Same as sinon.match.has but the property must be defined by the value itself. Inherited properties are ignored.

sinon.match.hasNested(propertyPath[, expectation])

Requires the value to define the given propertyPath. Dot (prop.prop) and bracket (prop[0]) notations are supported as in Lodash.get.

The propertyPath might be inherited via the prototype chain. If the optional expectation is given, the value at the propertyPath is deeply compared with the expectation. The expectation can be another matcher.

sinon.match.hasNested("a[0].b.c");

// Where actual is something like
var actual = { a: [{ b: { c: 3 } }] };

sinon.match.hasNested("a.b.c");

// Where actual is something like
var actual = { a: { b: { c: 3 } } };

sinon.match.every(matcher)

Requires every element of an Array, Set or Map, or alternatively every value of an Object to match the given matcher.

sinon.match.some(matcher)

Requires any element of an Array, Set or Map, or alternatively any value of an Object to match the given matcher.

Combining matchers

All matchers implement and and or. This allows to logically combine multiple matchers. The result is a new matcher that requires both (and) or one of the matchers (or) to return true.

var stringOrNumber = sinon.match.string.or(sinon.match.number);
var bookWithPages = sinon.match.instanceOf(Book).and(sinon.match.has("pages"));

Custom matchers

Custom matchers are created with the sinon.match factory which takes a test function and an optional message.

The test function takes a value as the only argument, returns true if the value matches the expectation and false otherwise. The message string is used to generate the error message in case the value does not match the expectation.

var trueIsh = sinon.match(function (value) {
  return !!value;
}, "trueIsh");