Top 10 Javascript interview questions : Concepts every javascript developer should know
interview questions , Javascript / August 20, 2018

1  Explain let,var and const variable declaration and explain their scope .what is strict mode? 2  What are callbacks and callback hell in javascript . What are higher order functions? 3 What is  hositing in javascript ? 4 What are prototypes and explain Prototypal inhertiance ? 5 What are Closures in javascript? 6 What are arrow functions / fat arrow functions  in Javascript? 7 What doe this keyword indicate in javascript? 8 What are promises in JavaScript? 9 What is bubbling and propogation in Javascript? 10 What are generators in Javascript? ANSWERS 1  The scope of var is the current execution context.That is, scope of var is global,if used outside a function and the scope is the function block if used inside the function. See more here  Understanding variable scope(let,var,const),hoisting in Javascript and Temporal Dead Zone(TDZ) 2  In  most programming languages , functions can accept other function(s) as arguments or return a function .Such functions are called Higher order functions.In JavaScript most APIs and Modules can accept function as an argument to a function .The functions are called  callbacks.see more here Understanding Callbacks and Callback hell in JavaScript : asynchronous behaviour of Javascript Part -1 3 To hoist means to pull or move up . Javascript hoisting means variable and function declarations are pulled to the top of the scope while…

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