Arrays, Objects & ES6+

Array methods, Spread/Rest, Promises, Higher Order Functions

Questions

1
intermediate

What is the difference between map() and forEach()?

mapforEacharrays
2
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What is the difference between map and filter?

mapfilterarrays
3
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What is the difference between find and findIndex?

findfindIndexarrays
4
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What is the spread operator (...) used for?

spread-operatores6arrays
5
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What is the rest operator (...) used for?

rest-operatores6functions
6
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What is the difference between slice and splice?

slicesplicearrays
intermediatePremium

What is the difference between Object.freeze() and Object.seal()?

freezesealobjects
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What are the differences between call(), apply() and bind()?

callapplybind
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What is a callback function?

callbacksfunctionsasync
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What is a Higher Order Function?

higher-order-functionsfunctional-programming
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What are Promises in JavaScript?

promisesasyncasynchronous
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What are the differences between Promise.all, allSettled, any, and race?

promisesasyncPromise.all
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What is the difference between Pure and Impure functions?

pure-functionsimpure-functionsfunctional-programming
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What is the difference between for-in and for-of?

for-infor-ofloops
intermediateMulti-selectPremium

What are the limitations of arrow functions? (Select all that apply)

arrow-functionses6functions
16
intermediate

What does the reduce() method do in JavaScript?

reducearraysfunctional-programming
17
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What is the difference between Object.keys(), Object.values(), and Object.entries()?

objectsObject.keysObject.values
18
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What is async/await in JavaScript?

async-awaitpromisesasynchronous
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What is optional chaining (?.) in JavaScript?

optional-chaininges2020null-safety
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What is the nullish coalescing operator (??)?

nullish-coalescingoperatorses2020
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What is the difference between Array.from() and Array.of()?

Array.fromArray.ofarrays
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What is debouncing in JavaScript?

debouncingperformanceoptimization