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JavaScriptBeginner#fundamentals#types
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JavaScript Interview Questions
50 questions · Closures, async, prototypes, ES6+ and core JavaScript interview questions.
50 results
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JavaScriptBeginner#scope#es6
Difference between var, let and const?
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JavaScriptBeginner#scope
What is hoisting?
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JavaScriptIntermediate#closures#functions
What is a closure?
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JavaScriptBeginner#operators#coercion
Explain == vs ===.
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JavaScriptBeginner#coercion
What are truthy and falsy values?
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JavaScriptIntermediate#this#functions
How does 'this' work in JavaScript?
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JavaScriptIntermediate#functions#this
Difference between call, apply and bind?
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JavaScriptIntermediate#functions#es6
Difference between arrow functions and regular functions?
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JavaScriptIntermediate#prototypes#oop
What is prototypal inheritance?
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JavaScriptIntermediate#oop#es6
What is the difference between an ES6 class and a constructor function?
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JavaScriptAdvanced#event-loop#async
Explain the event loop.
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JavaScriptAdvanced#event-loop#async
What are microtasks and macrotasks?
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JavaScriptIntermediate#async#promises
What is a Promise and what are its states?
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JavaScriptAdvanced#async#promises
Difference between Promise.all, allSettled, race and any?
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JavaScriptIntermediate#async
How does async/await work?
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JavaScriptIntermediate#async#performance
How do you run async calls in parallel with async/await?
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JavaScriptBeginner#async
What is callback hell and how do you avoid it?
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JavaScriptIntermediate#dom#events
What is event bubbling, capturing and delegation?
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JavaScriptIntermediate#dom#events
Difference between stopPropagation and preventDefault?
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JavaScriptAdvanced#performance#functions
What is debouncing and throttling?
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JavaScriptBeginner#arrays
Explain map, filter and reduce.
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JavaScriptBeginner#arrays
Difference between forEach and map?
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JavaScriptBeginner#arrays
Difference between slice and splice?
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JavaScriptBeginner#arrays
What do find, findIndex, some and every do?
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JavaScriptBeginner#es6
What is destructuring?
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JavaScriptBeginner#es6
Difference between spread and rest operators?
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JavaScriptIntermediate#objects
How do you deep clone an object?
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JavaScriptIntermediate#es6#operators
What is optional chaining and nullish coalescing?
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JavaScriptBeginner#fundamentals
Difference between null and undefined?
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JavaScriptIntermediate#es6#collections
Difference between Map/Set and plain objects/arrays?
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JavaScriptIntermediate#objects
What is the difference between shallow copy and deep copy?
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JavaScriptBeginner#es6#strings
What are template literals?
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JavaScriptAdvanced#functions
What is currying?
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JavaScriptIntermediate#functions
What is a higher-order function?
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JavaScriptAdvanced#performance#functions
What is memoization?
37
JavaScriptBeginner#browser#storage
What are localStorage, sessionStorage and cookies?
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JavaScriptIntermediate#browser#async
How does fetch differ from XMLHttpRequest?
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JavaScriptIntermediate#browser#security
What is CORS?
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JavaScriptBeginner#async
What is the difference between synchronous and asynchronous code?
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JavaScriptAdvanced#es6
What are generators and iterators?
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JavaScriptIntermediate#es6#modules
What is the difference between a module and a script? (import/export)
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JavaScriptIntermediate#objects
What is the difference between Object.freeze and const?
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JavaScriptBeginner#numbers
What is NaN and how do you check for it?
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JavaScriptIntermediate#numbers
Why is 0.1 + 0.2 !== 0.3?
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JavaScriptIntermediate#dom#events
What is event delegation useful for in dynamic lists?
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JavaScriptIntermediate#browser#performance
What is the difference between defer and async on a script tag?
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JavaScriptAdvanced#performance#memory
What causes memory leaks in JavaScript?
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JavaScriptBeginner#types
What is the difference between typeof and instanceof?
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JavaScriptIntermediate#fundamentals