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Reset/Clear with beforeEach/beforeAll and clearAllMocks/resetAllMocks Assuming we have a global stub or spy that is potentially called mutliple times throughout our tests. const mockFn = jest.fn(); function fnUnderTest(args1) { mockFn(args1); } test('Testing once', () => { fnUnderTest('first-call'); expect(mockFn).toHaveBeenCalledWith('first-call'); expect(mockFn).toHaveBeenCalledTimes(1); }); t..

Default parameters Default function parameters allow named parameters to be initialized with default values if no value or undefined is passed. Syntax function fnName(param1 = defaultValue1, ..., paramN = defaultValueN) { /* ... */ } Copy to Clipboard Description In JavaScript, function parameters default to undefined. However, it's often useful to set a different default value. This is where de..

Promise.resolve() The Promise.resolve() method returns a Promise object that is resolved with a given value. If the value is a promise, that promise is returned; if the value is a thenable (i.e. has a "then" method), the returned promise will "follow" that thenable, adopting its eventual state; otherwise the returned promise will be fulfilled with the value. This function flattens nested layers ..

Unlike Single-Master Database, every data has Read & Write permission with every user, and it updates data with each other. Data structures DynamoDB uses hashing and B-trees to manage data. Upon entry, data is first distributed into different partitions by hashing on the partition key. Each partition can store up to 10GB of data and handle by default 1,000 write capacity units (WCU) and 3,000 re..

BYU Broadcast Test Code System: (Code that I'm working on) Unit Test Individual Tests with every function Integration Test Test to see if it integrates with the system End to End Test Test from beginning to the End Deploy Check for deploying Check if it actually connects well with Each Area of AWS (Ex: US-East1) BYU Broadcast ServiceStream: (Code that I'm working on) CreateMedia UpdateStatusWait..

With the dramatic rise of functional programming in mainstream JavaScript, curried functions have become common in many applications. It’s important to understand what they are, how they work, and how to put them to good use. What is a curried function? A curried function is a function that takes multiple arguments one at a time. Given a function with 3 parameters, the curried version will take ..

Rest parameters The rest parameter syntax allows a function to accept an indefinite number of arguments as an array, providing a way to represent variadic functions in JavaScript. Syntax function f(a, b, ...theArgs) { // ... } Copy to Clipboard Description A function definition's last parameter can be prefixed with "..." (three U+002E FULL STOP characters), which will cause all remaining (user s..

Arrow function expressions An arrow function expression is a compact alternative to a traditional function expression, but is limited and can't be used in all situations. There are differences between arrow functions and traditional functions, as well as some limitations: Arrow functions don't have their own bindings to this or super, and should not be used as methods. Arrow functions don't have..

Mock Functions Mock functions allow you to test the links between code by erasing the actual implementation of a function, capturing calls to the function (and the parameters passed in those calls), capturing instances of constructor functions when instantiated with new, and allowing test-time configuration of return values. There are two ways to mock functions: Either by creating a mock functio..

Solve - date.getTime is not a function Error # The "date.getTime is not a function" error occurs when the getTime() method is called on a value that is not a date object. To solve the error, convert the value to a date before calling the method or make sure to only call the getTime() method on valid date objects. Here is an example of how the error occurs. index.js const date = Date.now(); conso..