| 1 | What are the possible ways to create objects in JavaScript? |
| 2 | What is prototype chain? |
| 3 | What is the difference between Call, Apply and Bind? |
| 4 | What is JSON and its common operations |
| 5 | What is the purpose of array slice method? |
| 6 | What is the purpose of array splice method? |
| 7 | What is the difference between slice and splice? |
| 8 | How do you compare Object and Map? |
| 9 | What is the difference between == and === operators? |
| 10 | What are lambda or arrow functions? |
| 11 | What is a first class function? |
| 12 | What is a first order function? |
| 13 | What is a higher order function? |
| 14 | What is a unary function? |
| 15 | What is currying function? |
| 16 | What is a pure function? |
| 17 | What is the purpose of let keyword? |
| 18 | What is the difference between let and var? |
| 19 | What is the reason to choose the name let as keyword? |
| 20 | How do you redeclare variables in switch block without an error? |
| 21 | What is Temporal Dead Zone? |
| 22 | What is IIFE(Immediately Invoked Function Expression)? |
| 23 | What is the benefit of using modules? |
| 24 | What is memoization? |
| 25 | What is Hoisting? |
| 26 | What are classes in ES6? |
| 27 | What are closures? |
| 28 | What are modules? |
| 29 | Why do you need modules? |
| 30 | What is scope in javascript? |
| 31 | What is a service worker? |
| 32 | How do you manipulate DOM using service worker? |
| 33 | How do you reuse information across service worker restarts? |
| 34 | What is IndexedDB? |
| 35 | What is web storage? |
| 36 | What is a post message? |
| 37 | What is a cookie? |
| 38 | Why do you need a Cookie? |
| 39 | What are the options in a cookie? |
| 40 | How do you delete a cookie? |
| 41 | What are the differences between cookie, local storage and session storage? |
| 42 | What is the main difference between localStorage and sessionStorage? |
| 43 | How do you access web storage? |
| 44 | What are the methods available on session storage? |
| 45 | What is a storage event and its event handler? |
| 46 | Why do you need web storage? |
| 47 | How do you check web storage browser support? |
| 48 | How do you check web workers browser support? |
| 49 | Give an example of web worker? |
| 50 | What are the restrictions of web workers on DOM? |
| 51 | What is a promise? |
| 52 | Why do you need a promise? |
| 53 | What are the three states of promise? |
| 54 | What is a callback function? |
| 55 | Why do we need callbacks? |
| 56 | What is a callback hell? |
| 57 | What is server-sent events? |
| 58 | How do you receive server-sent event notifications? |
| 59 | How do you check browser support for server-sent events? |
| 60 | What are the events available for server sent events? |
| 61 | What are the main rules of promise? |
| 62 | What is callback in callback? |
| 63 | What is promise chaining? |
| 64 | What is promise.all |
| 65 | What is the purpose of race method in promise? |
| 66 | What is a strict mode in javascript? |
| 67 | Why do you need strict mode? |
| 68 | How do you declare strict mode? |
| 69 | What is the purpose of double exclamation? |
| 70 | What is the purpose of delete operator? |
| 71 | What is typeof operator? |
| 72 | What is undefined property? |
| 73 | What is null value? |
| 74 | What is the difference between null and undefined? |
| 75 | What is eval? |
| 76 | What is the difference between window and document? |
| 77 | How do you access history in javascript? |
| 78 | What are the javascript data types? |
| 79 | What is isNaN? |
| 80 | What are the differences between undeclared and undefined variables? |
| 81 | What are global variables? |
| 82 | What are the problems with global variables? |
| 83 | What is NaN property? |
| 84 | What is the purpose of isFinite function? |
| 85 | What is an event flow? |
| 86 | What is event bubbling? |
| 87 | What is event capturing? |
| 88 | How do you submit a form using JavaScript? |
| 89 | How do you find operating system details? |
| 90 | What is the difference between document load and DOMContentLoaded events? |
| 91 | What is the difference between native, host and user objects? |
| 92 | What are the tools or techniques used for debugging JavaScript code? |
| 93 | What are the pros and cons of promises over callbacks? |
| 94 | What is the difference between an attribute and a property? |
| 95 | What is same-origin policy? |
| 96 | What is the purpose of void 0? |
| 97 | Is JavaScript a compiled or interpreted language? |
| 98 | Is JavaScript a case-sensitive language? |
| 99 | Is there any relation between Java and JavaScript? |
| 100 | What are events? |
| 101 | Who created javascript? |
| 102 | What is the use of preventDefault method? |
| 103 | What is the use of stopPropagation method? |
| 104 | What are the steps involved in return false? |
| 105 | What is BOM? |
| 106 | What is the use of setTimeout? |
| 107 | What is the use of setInterval? |
| 108 | Why is JavaScript treated as Single threaded? |
| 109 | What is an event delegation? |
| 110 | What is ECMAScript? |
| 111 | What is JSON? |
| 112 | What are the syntax rules of JSON? |
| 113 | What is the purpose JSON stringify? |
| 114 | How do you parse JSON string? |
| 115 | Why do you need JSON? |
| 116 | What are PWAs? |
| 117 | What is the purpose of clearTimeout method? |
| 118 | What is the purpose of clearInterval method? |
| 119 | How do you redirect new page in javascript? |
| 120 | How do you check whether a string contains a substring? |
| 121 | How do you validate an email in javascript? |
| 122 | How do you get the current url with javascript? |
| 123 | What are the various url properties of location object? |
| 124 | How do get query string values in javascript? |
| 125 | How do you check if a key exists in an object? |
| 126 | How do you loop through or enumerate javascript object? |
| 127 | How do you test for an empty object? |
| 128 | What is an arguments object? |
| 129 | How do you make first letter of the string in an uppercase? |
| 130 | What are the pros and cons of for loop? |
| 131 | How do you display the current date in javascript? |
| 132 | How do you compare two date objects? |
| 133 | How do you check if a string starts with another string? |
| 134 | How do you trim a string in javascript? |
| 135 | How do you add a key value pair in javascript? |
| 136 | Is the '!--' notation represents a special operator? |
| 137 | How do you assign default values to variables? |
| 138 | How do you define multiline strings? |
| 139 | What is an app shell model? |
| 140 | Can we define properties for functions? |
| 141 | What is the way to find the number of parameters expected by a function? |
| 142 | What is a polyfill? |
| 143 | What are break and continue statements? |
| 144 | What are js labels? |
| 145 | What are the benefits of keeping declarations at the top? |
| 146 | What are the benefits of initializing variables? |
| 147 | What are the recommendations to create new object? |
| 148 | How do you define JSON arrays? |
| 149 | How do you generate random integers? |
| 150 | Can you write a random integers function to print integers with in a range? |
| 151 | What is tree shaking? |
| 152 | What is the need of tree shaking? |
| 153 | Is it recommended to use eval? |
| 154 | What is a Regular Expression? |
| 155 | What are the string methods available in Regular expression? |
| 156 | What are modifiers in regular expression? |
| 157 | What are regular expression patterns? |
| 158 | What is a RegExp object? |
| 159 | How do you search a string for a pattern? |
| 160 | What is the purpose of exec method? |
| 161 | How do you change style of a HTML element? |
| 162 | What would be the result of 1+2+'3'? |
| 163 | What is a debugger statement? |
| 164 | What is the purpose of breakpoints in debugging? |
| 165 | Can I use reserved words as identifiers? |
| 166 | How do you detect a mobile browser? |
| 167 | How do you detect a mobile browser without regexp? |
| 168 | How do you get the image width and height using JS? |
| 169 | How do you make synchronous HTTP request? |
| 170 | How do you make asynchronous HTTP request? |
| 171 | How do you convert date to another timezone in javascript? |
| 172 | What are the properties used to get size of window? |
| 173 | What is a conditional operator in javascript? |
| 174 | Can you apply chaining on conditional operator? |
| 175 | What are the ways to execute javascript after page load? |
| 176 | What is the difference between proto and prototype? |
| 177 | Give an example where do you really need semicolon? |
| 178 | What is a freeze method? |
| 179 | What is the purpose of freeze method? |
| 180 | Why do I need to use freeze method? |
| 181 | How do you detect a browser language preference? |
| 182 | How to convert string to title case with javascript? |
| 183 | How do you detect javascript disabled in the page? |
| 184 | What are various operators supported by javascript? |
| 185 | What is a rest parameter? |
| 186 | What happens if you do not use rest parameter as a last argument? |
| 187 | What are the bitwise operators available in javascript? |
| 188 | What is a spread operator? |
| 189 | How do you determine whether object is frozen or not? |
| 190 | How do you determine two values same or not using object? |
| 191 | What is the purpose of using object is method? |
| 192 | How do you copy properties from one object to other? |
| 193 | What are the applications of assign method? |
| 194 | What is a proxy object? |
| 195 | What is the purpose of seal method? |
| 196 | What are the applications of seal method? |
| 197 | What are the differences between freeze and seal methods? |
| 198 | How do you determine if an object is sealed or not? |
| 199 | How do you get enumerable key and value pairs? |
| 200 | What is the main difference between Object.values and Object.entries method? |
| 201 | How can you get the list of keys of any object? |
| 202 | How do you create an object with prototype? |
| 203 | What is a WeakSet? |
| 204 | What are the differences between WeakSet and Set? |
| 205 | List down the collection of methods available on WeakSet? |
| 206 | What is a WeakMap? |
| 207 | What are the differences between WeakMap and Map? |
| 208 | List down the collection of methods available on WeakMap? |
| 209 | What is the purpose of uneval? |
| 210 | How do you encode an URL? |
| 211 | How do you decode an URL? |
| 212 | How do you print the contents of web page? |
| 213 | What is the difference between uneval and eval? |
| 214 | What is an anonymous function? |
| 215 | What is the precedence order between local and global variables? |
| 216 | What are javascript accessors? |
| 217 | How do you define property on Object constructor? |
| 218 | What is the difference between get and defineProperty? |
| 219 | What are the advantages of Getters and Setters? |
| 220 | Can I add getters and setters using defineProperty method? |
| 221 | What is the purpose of switch-case? |
| 222 | What are the conventions to be followed for the usage of swtich case? |
| 223 | What are primitive data types? |
| 224 | What are the different ways to access object properties? |
| 225 | What are the function parameter rules? |
| 226 | What is an error object? |
| 227 | When you get a syntax error? |
| 228 | What are the different error names from error object? |
| 229 | What are the various statements in error handling? |
| 230 | What are the two types of loops in javascript? |
| 231 | What is nodejs? |
| 232 | What is an Intl object? |
| 233 | How do you perform language specific date and time formatting? |
| 234 | What is an Iterator? |
| 235 | What is an event loop? |
| 236 | What is call stack? |
| 237 | What is an event queue? |
| 238 | What is a decorator? |
| 239 | What are the properties of Intl object? |
| 240 | What is an Unary operator? |
| 241 | How do you sort elements in an array? |
| 242 | What is the purpose of compareFunction while sorting arrays? |
| 243 | How do you reversing an array? |
| 244 | How do you find min and max value in an array? |
| 245 | How do you find min and max values without Math functions? |
| 246 | What is an empty statement and purpose of it? |
| 247 | How do you get meta data of a module? |
| 248 | What is a comma operator? |
| 249 | What is the advantage of a comma operator? |
| 250 | What is typescript? |
| 251 | What are the differences between javascript and typescript? |
| 252 | What are the advantages of typescript over javascript? |
| 253 | What is an object initializer? |
| 254 | What is a constructor method? |
| 255 | What happens if you write constructor more than once in a class? |
| 256 | How do you call the constructor of a parent class? |
| 257 | How do you get the prototype of an object? |
| 258 | What happens If I pass string type for getPrototype method? |
| 259 | How do you set prototype of one object to another? |
| 260 | How do you check whether an object can be extendable or not? |
| 261 | How do you prevent an object to extend? |
| 262 | What are the different ways to make an object non-extensible? |
| 263 | How do you define multiple properties on an object? |
| 264 | What is MEAN in javascript? |
| 265 | What Is Obfuscation in javascript? |
| 266 | Why do you need Obfuscation? |
| 267 | What is Minification? |
| 268 | What are the advantages of minification? |
| 269 | What are the differences between Obfuscation and Encryption? |
| 270 | What are the common tools used for minification? |
| 271 | How do you perform form validation using javascript? |
| 272 | How do you perform form validation without javascript? |
| 273 | What are the DOM methods available for constraint validation? |
| 274 | What are the available constraint validation DOM properties? |
| 275 | What are the list of validity properties? |
| 276 | Give an example usage of rangeOverflow property? |
| 277 | Is enums feature available in javascript? |
| 278 | What is an enum? |
| 279 | How do you list all properties of an object? |
| 280 | How do you get property descriptors of an object? |
| 281 | What are the attributes provided by a property descriptor? |
| 282 | How do you extend classes? |
| 283 | How do I modify the url without reloading the page? |
| 284 | How do you check whether an array includes a particular value or not? |
| 285 | How do you compare scalar arrays? |
| 286 | How to get the value from get parameters? |
| 287 | How do you print numbers with commas as thousand separators? |
| 288 | What is the difference between java and javascript? |
| 289 | Is javascript supports namespace? |
| 290 | How do you declare namespace? |
| 291 | How do you invoke javascript code in an iframe from parent page? |
| 292 | How do get the timezone offset from date? |
| 293 | How do you load CSS and JS files dynamically? |
| 294 | What are the different methods to find HTML elements in DOM? |
| 295 | What is jQuery? |
| 296 | What is V8 JavaScript engine? |
| 297 | Why do we call javascript as dynamic language? |
| 298 | What is a void operator? |
| 299 | How to set the cursor to wait? |
| 300 | How do you create an infinite loop? |
| 301 | Why do you need to avoid with statement? |
| 302 | What is the output of below for loops? |
| 303 | List down some of the features of ES6? |
| 304 | What is ES6? |
| 305 | Can I redeclare let and const variables? |
| 306 | Is const variable makes the value immutable? |
| 307 | What are default parameters? |
| 308 | What are template literals? |
| 309 | How do you write multi-line strings in template literals? |
| 310 | What are nesting templates? |
| 311 | What are tagged templates? |
| 312 | What are raw strings? |
| 313 | What is destructuring assignment? |
| 314 | What are default values in destructuring assignment? |
| 315 | How do you swap variables in destructuring assignment? |
| 316 | What are enhanced object literals? |
| 317 | What are dynamic imports? |
| 318 | What are the use cases for dynamic imports? |
| 319 | What are typed arrays? |
| 320 | What are the advantages of module loaders? |
| 321 | What is collation? |
| 322 | What is for...of statement? |
| 323 | What is the output of below spread operator array? |
| 324 | Is PostMessage secure? |
| 325 | What are the problems with postmessage target origin as wildcard? |
| 326 | How do you avoid receiving postMessages from attackers? |
| 327 | Can I avoid using postMessages completely? |
| 328 | Is postMessages synchronous? |
| 329 | What paradigm is Javascript? |
| 330 | What is the difference between internal and external javascript? |
| 331 | Is JavaScript faster than server side script? |
| 332 | How do you get the status of a checkbox? |
| 333 | What is the purpose of double tilde operator? |
| 334 | How do you convert character to ASCII code? |
| 335 | What is ArrayBuffer? |
| 336 | What is the output of below string expression? |
| 337 | What is the purpose of Error object? |
| 338 | What is the purpose of EvalError object? |
| 339 | What are the list of cases error thrown from non-strict mode to strict mode? |
| 340 | Is all objects have prototypes? |
| 341 | What is the difference between a parameter and an argument? |
| 342 | What is the purpose of some method in arrays? |
| 343 | How do you combine two or more arrays? |
| 344 | What is the difference between Shallow and Deep copy? |
| 345 | How do you create specific number of copies of a string? |
| 346 | How do you return all matching strings against a regular expression? |
| 347 | How do you trim a string at the beginning or ending? |
| 348 | What is the output of below console statement with unary operator? |
| 349 | Does javascript uses mixins? |
| 350 | What is a thunk function? |
| 351 | What are asynchronous thunks? |
| 352 | What is the output of below function calls? |
| 353 | How to remove all line breaks from a string? |
| 354 | What is the difference between reflow and repaint? |
| 355 | What happens with negating an array? |
| 356 | What happens if we add two arrays? |
| 357 | What is the output of prepend additive operator on falsy values? |
| 358 | How do you create self string using special characters? |
| 358 | How do you remove falsy values from an array? |
| 359 | How do you get unique values of an array? |
| 360 | What is destructuring aliases? |
| 361 | How do you map the array values without using map method? |
| 362 | How do you empty an array? |
| 363 | How do you rounding numbers to certain decimals |
| 364 | What is the easiest way to convert an array to an object? |
| 365 | How do you create an array with some data? |
| 366 | What are the placeholders from console object? |
| 367 | Is it possible to add CSS to console messages? |
| 368 | What is the purpose of dir method of console object? |
| 369 | Is it possible to debug HTML elements in console? |
| 370 | How do you display data in a tabular format using console object? |
| 371 | How do you verify that an argument is a Number or not? |
| 372 | How do you create copy to clipboard button? |
| 373 | What is the shortcut to get timestamp? |
| 374 | How do you flattening multi dimensional arrays? |
| 375 | What is the easiest multi condition checking? |
| 376 | How do you capture browser back button? |
| 377 | How do you disable right click in the web page? |
| 378 | What are wrapper objects? |
| 379 | What is AJAX? |
| 380 | What are the different ways to deal with Asynchronous Code? |
| 381 | How to cancel a fetch request? |
| 382 | What is web speech API? |
| 383 | What is minimum timeout throttling? |
| 384 | How do you implement zero timeout in modern browsers? |
| 385 | What are tasks in event loop? |
| 386 | What are microtasks? |
| 387 | What are different event loops? |
| 388 | What is the purpose of queueMicrotask? |
| 389 | How do you use javascript libraries in typescript file? |
| 390 | What are the differences between promises and observables? |
| 391 | What is heap? |
| 392 | What is an event table? |
| 393 | What is a microTask queue? |
| 394 | What is the difference between shim and polyfill? |
| 395 | How do you detect primitive or non primitive value type? |
| 396 | What is babel? |
| 397 | Is Node.js completely single threaded? |
| 398 | What are the common use cases of observables? |
| 399 | What is RxJS? |
| 400 | What is the difference between Function constructor and function declaration? |
| 401 | What is a Short circuit condition? |
| 402 | What is the easiest way to resize an array? |
| 403 | What is an observable? |
| 404 | What is the difference between function and class declarations? |
