Introduction to ES6 Interview Questions and Answers
If you are looking for a job related to ES6, you need to prepare for the 2020 ES6 Interview Questions. Every interview is different from the different job profiles, but still, to clear the interview, you need to have a good and clear knowledge of ES6 processes. Here, we have prepared the important ES6 Interview Question and answers that will help you succeed in your interview.
These questions are divided into two parts are as follows:
Part 1 – ES6 Interview Questions (Basic)
This first part covers basic ES6 Interview Questions and Answers.
Q1. Define ES6 and mention the new features of ES6?
Refer to the introduction part for the definition of ES6. Below are the new features listed:
- Constants (Immutable variables)
- Arrow functions
- Extended parameter handling
- Template literals
- Extended literals
- Enhanced Regular expressions
- Enhanced object properties.
- Destructuring Assignment
- Symbol Type
- Map/Set & WeakMap/WeakSet
- Typed Arrays
- Built-in Methods
- Internationalization and Localization.
Q2. How do you use ES6, or the best way to use ES6 in a project?
Let us move to the next ES6 Interview Questions.
Q3. What are Constants in ES6?
Constants are also referred to as Immutable variables. It means that the value of a constant variable cannot be changed. The value that has been assigned at the time of the declaration remains unchanged. E.g. const X= 5.0, here the value of X remains 5 every time, and it cannot be changed.
Q4. What are Block Scoped variables and functions?
This is the common ES6 Interview Question that is asked in an interview. The variables and functions are defined as indefinite blocks. It means these can be used where the variables and functions are defined or declared. If we have declared variable and function in any function block, their scope will be limited to that function only; they cannot be accessible outside the block/function. ‘Const’ keyword cannot change the value of a variable. ‘let’ keyword allows variable value to be re-assigned; it can be in for loop or arrays.
Q5. Explain briefly about Arrow functions?
Arrow functions support expressions bodies and statement bodies which returns the expression’s value and makes the syntax more expressive. Arrow functions have lexical ‘this’ feature as well. Arrow (=>) is used as part of the syntax. Lexical, this is declared or defined where the function is written. It comes under the umbrella of lexical scope; lexical scope has access to variables that are in its parent scope.
Part 2 – ES6 Interview Questions (Advanced)
Let us now have a look at the advanced ES6 Interview Questions and Answers.
Q6. Explain about Webpack and the benefits of using Webpack?
Q7. Explain about Default parameter values, Rest parameter, Spread operator?
Default parameter values are used to initialize the functions with default values. The value of a parameter can be anything like a null value, number or function.
The rest parameter is used to retrieve all the arguments to invoke the function. It means we can push the items of different categories separately. The rest parameter uses the rest parameter to combine parameters into a single array parameter.
A spread operator is donated by …, and then the variable name has been provided. E.g. ‘…X’ syntax of spread operator. It has been used to manipulate objects and array in ES6 and to copy the enumerable properties from one object to another.
Let us move to the next ES6 Interview Questions.
Q8. Explain about Internationalization and localization?
- Collation: It is used for searching within a set of strings and sorting a set of strings. It is parameterized by locale and aware of Unicode.
- Number Formatting: Numbers can be formatted with localized separators and digit grouping. The other things that include are style formatting, numbering system, percent, and precision.
- Currency formatting: Numbers can be formatted mainly with currency symbols, with localized separators and digit grouping.
- Date and time formatting: it has been formatted with localized separators and ordering. The format can be short, long and other parameters like locale and time zone.
Q9. What is a Destructuring assignment, and explain in brief?
This is the frequently asked ES6 Interview Questions which is asked in an interview. Destructuring assignment is used to bind the set of a variable to the corresponding values. It mainly refers to the use of patterns to extract the parts of an object. A destructuring assignment has different forms like array matching, object matching, shorthand notation, object matching, deep matching, object and array matching, default values, parameter context matching, and fail-soft destruct. Some are explained as:
- Array matching/object matching, shorthand notation/ object matching, deep matching: It is intuitive and flexible of arrays into individual variables during an assignment.
- Object and Array matching: It is simple and defined default values for destructuring of objects and arrays.
Q10. Explain briefly about classes, modules, and proxies?
Classes are based on the OOP style that is object-oriented programming. The class declaration makes the patterns easier to use. It supports inheritance, base class access, static methods, and constructors.
- Proxies: It enables object creation with a wide variety of behaviours available to host objects. It can be used for logging, profiling, etc.
This has been a guide to the List Of ES6 Interview Questions and Answers so that the candidate can crackdown these ES6 Interview Questions easily. Here in this post, we have studied top ES6 Interview Questions, which are often asked in interviews. You may also look at the following articles to learn more –
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