|
1 | | -# JavaScript-Interview-Questions-2023 |
| 1 | +--- |
| 2 | +title: "Tricky Javascript Code Snippets Asked in the Interview (es6/es7/es8/es9)" |
| 3 | +description: "Prepare for your next 2023 JavaScript interview with these tricky code snippets. Covering ES6/ES7/ES8/ES9 syntax and features, this article provides examples and explanations to help you ace your interview." |
| 4 | +githubPath: "https://github.com/Vasu7389/JavaScript-Interview-Questions-2023" |
| 5 | +--- |
| 6 | + |
| 7 | +<span style=" font-size: 0.8rem; border-bottom: 1px solid grey;"> Updated Dec 31, 2022 </span> |
| 8 | + |
| 9 | +In this article, we will cover a range of JavaScript interview questions, including those related to the latest versions of the language (ES6, ES7, ES8, and ES9). |
| 10 | + |
| 11 | +We'll also compare the differences between ES5 and the newer versions of the language and provide examples of ES6 code snippets. |
| 12 | + |
| 13 | +Additionally, we'll include multiple choice questions (MCQs) on ES6 and explore some of the trickiest code snippets that are commonly asked in JavaScript interviews. |
| 14 | + |
| 15 | +Whether you're preparing for a job interview or simply want to brush up on your knowledge of the language, this article has something for you. |
| 16 | + |
| 17 | +## Javascript ES6 ES7 ES8 |
| 18 | + |
| 19 | +ECMAScript (ES) is a standardized version of JavaScript, a programming language that is widely used to create interactive web pages and applications. ECMAScript is a formal specification developed and maintained by the Ecma International organization. |
| 20 | + |
| 21 | +JavaScript is a programming language that is commonly used to create interactive web pages and applications. It is based on the ECMAScript specification and is an implementation of it. JavaScript is a client-side scripting language, meaning it is executed by the user's web browser rather than a server. It is used to create dynamic and interactive elements on web pages, such as form validation, image sliders, and modal windows. |
| 22 | + |
| 23 | +ECMAScript and JavaScript are closely related, and the terms are often used interchangeably. However, ECMAScript is the formal specification, and JavaScript is the implementation of that specification. |
| 24 | + |
| 25 | +<span style=" font-size: 0.5rem;"> \*Discover the answers by clicking on the questions.</span> |
| 26 | + |
| 27 | +<details> |
| 28 | +<summary> |
| 29 | + <h3>1. Guess the output of this code? |
| 30 | + |
| 31 | +```js |
| 32 | +let a = {}; |
| 33 | +let b = { key: "b" }; |
| 34 | +let c = { key: "c" }; |
| 35 | + |
| 36 | +a[b] = 123; |
| 37 | +a[c] = 456; |
| 38 | + |
| 39 | +console.log(a[b]); |
| 40 | +``` |
| 41 | + |
| 42 | +</h3> |
| 43 | +</summary> |
| 44 | + |
| 45 | +The output of this code will be `456`. |
| 46 | + |
| 47 | +In this code, a is an empty object that is being assigned properties using the square bracket notation. The values of the properties are being set to the numbers `123` and `456`. The keys of the properties are the objects b and c. |
| 48 | + |
| 49 | +When the `console.log` statement is executed, it logs the value of the property of a whose `key` is the object `b`. In this case, the value of this property is 456, because the value of the property was last set to 456 when the object c was used as the key. |
| 50 | + |
| 51 | +This behavior occurs because when objects are used as keys in an object, the object's default behavior is to convert the object to a string representation. In this case, both b and c are converted to the string `[object Object]`, which means that they both end up being used as the same key in the a object. As a result, the value of the property that is set using the object c as the key overwrites the value of the property that was set using the object b as the key. |
| 52 | + |
| 53 | +So the object `a` looks like - |
| 54 | + |
| 55 | +```js |
| 56 | +{ |
| 57 | + "[object Object]": 456 |
| 58 | +} |
| 59 | +``` |
| 60 | + |
| 61 | +</details> |
0 commit comments