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InterviewSolution
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Explain async and await in JavaScript. |
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Answer» Async/Await is a SPECIAL SYNTAX that allows developers to work with JavaScript promises in an easier and more comfortable manner. Async is a keyword that is written before a function definition, which indicates that the function always returns a promise. Await is a keyword that is used inside a function marked async. You cannot use await in a not async function. The await keyword makes JavaScript wait until a promise is settled and the result is RETURNED. Example, async function fetchData() { LET promise = new Promise((RESOLVE, reject) => { setTimeout(() => { resolve(‘Promise is successful’);}, 2000); }); let result = await promise; console.log(result); }Running the above function will log ‘Promise is successful’ after 2 seconds in the console. The function call fetchData() will return a promise which is later resolved to the value ‘Promise is successful’. On the line let result = await promise;JavaScript waits for the promise variable to be resolved before the value is returned to the result variable. |
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