Sometimes, we want to mock a TypeScript interface with Jest.
In this article, we’ll look at how to mock a TypeScript interface with Jest.
How to mock a TypeScript interface with Jest?
To mock a TypeScript interface with Jest, we just need to create objects that match the shape of the interface.
For instance, we write
mathlib.multiplier = {
multiply: jest.fn((a, b) => a * b),
};
to mock the multiply function with jest.fn assuming the multiply method looks like
interface IMultiplier {
multiply(a: number, b: number): number;
}
The mocked function takes 2 numbers as arguments and returns a number, and we have the same signature and return type in the mocked function.
So no error will be raised.
Conclusion
To mock a TypeScript interface with Jest, we just need to create objects that match the shape of the interface.
