number

toBeNumber

Use .toBeNumber when checking if a value is a Number.

test('passes when value is a number', () => {
expect(1).toBeNumber();
expect(NaN).toBeNumber();
expect(Infinity).toBeNumber();
expect(true).not.toBeNumber();
});

Tests

.toBeNaN()

Use .toBeNaN when checking a value is NaN.

test('passes when value is NaN', () => {
expect(NaN).toBeNaN();
expect(1).not.toBeNaN();
});

Tests

.toBeFinite()

Use .toBeFinite when checking if a value is a Number, not NaN or Infinity, or a BigInt.

test('passes when value is a finite number or bigint', () => {
expect(1).toBeFinite();
expect(BigInt(123456789)).toBeFinite();
expect(Infinity).not.toBeFinite();
expect(NaN).not.toBeFinite();
});

Tests

.toBePositive()

Use .toBePositive when checking if a value is a positive Number or BigInt.

test('passes when value is a positive number or bigint', () => {
expect(1).toBePositive();
expect(BigInt(42)).toBePositive();
expect(Infinity).not.toBePositive();
expect(-1).not.toBePositive();
expect(-BigInt(42)).not.toBePositive();
expect(NaN).not.toBePositive();
});

Tests

.toBeNegative()

Use .toBeNegative when checking if a value is a negative Number or BigInt.

test('passes when value is a negative number or bigint', () => {
expect(-1).toBeNegative();
expect(BigInt(-123)).toBeNegative();
expect(-Infinity).not.toBeNegative();
expect(1).not.toBeNegative();
expect(BigInt(123)).not.toBeNegative();
expect(NaN).not.toBeNegative();
});

Tests

.toBeEven()

Use .toBeEven when checking if a value is an even Number or BigInt.

test('passes when value is an even number or bigint', () => {
expect(2).toBeEven();
expect(BigInt(2)).toBeEven();
expect(BigInt(-4)).toBeEven();
expect(1).not.toBeEven();
expect(BigInt(1)).not.toBeEven();
expect(NaN).not.toBeEven();
});

Tests

.toBeOdd()

Use .toBeOdd when checking if a value is an odd Number or BigInt.

test('passes when value is an odd number or bigint', () => {
expect(1).toBeOdd();
expect(BigInt(1)).toBeOdd();
expect(BigInt(-3)).toBeOdd();
expect(2).not.toBeOdd();
expect(BigInt(2)).not.toBeOdd();
expect(NaN).not.toBeOdd();
});

Tests

.toBeWithin(start, end)

Use .toBeWithin when checking if a number is in between the given bounds of: start (inclusive) and end (exclusive).

test('passes when number is within given bounds', () => {
expect(1).toBeWithin(1, 3);
expect(2).toBeWithin(1, 3);
expect(3).not.toBeWithin(1, 3);
});

Tests

.toBeInteger()

Use .toBeInteger when checking if a value is an integer Number or any BigInt.

test('passes when value is an integer or bigint', () => {
expect(1).toBeInteger();
expect(1.0).toBeInteger();
expect(BigInt(42)).toBeInteger();
expect(1.1).not.toBeInteger();
});

Tests

.toBeInRange()

Use .toBeInRange when checking if an array's elements all fall within a range (min inclusive, max exclusive). Now supports BigInt values.

test('passes when all array elements are in range', () => {
expect([4, 5, 7, 9]).toBeInRange(4, 10);
expect([4n, 5n, 7n, 9n]).toBeInRange(4n, 10n);
expect([4, 5, 10]).not.toBeInRange(4, 10);
});

Tests

.toChangeBy()

Use .toChangeBy when checking if a function call changes a value by a specified amount. Now supports BigInt values.

test('passes when value changes by the specified amount', () => {
let value = 0;
let bigValue = BigInt(0);
expect(() => { value += 2 }).toChangeBy(() => value, 2);
expect(() => { bigValue += 2n }).toChangeBy(() => bigValue, 2n);
expect(() => { value += 1 }).not.toChangeBy(() => value, 2);
});

Tests

.toChangeTo()

Use .toChangeTo when checking if a function call changes a value to a specified value.

test('passes when value changes to the specified value', () => {
let value = 0;
let bigValue = BigInt(0);
expect(() => { value = 2 }).toChangeTo(() => value, 2);
expect(() => { bigValue = 42n }).toChangeTo(() => bigValue, 42n);
expect(() => { value = 3 }).not.toChangeTo(() => value, 2);
});

Tests