Accenture Reactjs Developer Interview Questions and Answers

Flatten an array without using inbuilt methods

• Use recursion to iterate through the array and flatten it

• Create a new array to store the flattened elements

• Check if each element is an array, if so, recursively call the function to flatten it

Sorting objects by age involves comparing age properties and rearranging them in ascending or descending order.

• Use the JavaScript `sort()` method to sort the array of objects.

• Example: `array.sort((a, b) => a.age - b.age)` for ascending order.

• For descending order, use: `array.sort((a, b) => b.age - a.age)`.

• Ensure the age property exists in each object to avoid errors.

useState manages state, while useEffect handles side effects in functional components.

• useState initializes state: const [count, setCount] = useState(0);

• useEffect runs side effects: useEffect(() => { document.title = `Count: ${count}`; }, [count]);

• useState can hold any data type: const [user, setUser] = useState({ name: '', age: 0 });

• useEffect can mimic lifecycle methods: useEffect(() => { fetchData(); }, []); for...read more

Arrow functions are used for concise syntax, lexical scoping of 'this', and implicit return of single expressions.

• Arrow functions have a more concise syntax compared to traditional function expressions.

• Arrow functions do not bind their own 'this' value, instead they inherit 'this' from the containing scope.

• Arrow functions automatically return the result of a single expression without needing the 'return' keyword.

Destructuring syntax allows for easy extraction of values from arrays or objects in JavaScript.

• Simplifies code by providing a concise way to extract multiple values from arrays or objects

• Improves readability and maintainability of code

• Can be used in function parameters to destructure objects directly

• Example: const person = { name: 'John', age: 30 }; const { name, age } = person;

React is a JavaScript library for building user interfaces that uses a virtual DOM to efficiently update the UI.

• React creates a virtual DOM to represent the UI components.

• When state or props change, React compares the virtual DOM with the actual DOM and updates only the necessary parts.

• React uses a component-based architecture to build reusable UI elements.

• React uses JSX, a syntax extension for JavaScript, to write com...read more

Redux is a predictable state container for JavaScript apps.

• Redux stores the entire state of the application in a single immutable object.

• Actions are dispatched to describe state changes.

• Reducers specify how the state changes in response to actions.

• Components can subscribe to the Redux store to access the state.

• Redux helps manage the state of complex applications and makes it easier to debug and test.

• Example: dispatchin...read more