From the course: Mastering Web Developer Interview Code
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What is variable hoisting and how do you guard against it?
From the course: Mastering Web Developer Interview Code
What is variable hoisting and how do you guard against it?
- [Instructor] JavaScript can be a tough language to learn, and often during interviews, you'll be presented with some code and asked to show what the result of that code will yield. So this week we're going to take a look at a classic issue that can trip people up during interviews, and that's hoisting. Now, with JavaScript variable and function declarations are processed before the code is executed, and this is what we call the hoisting, because in essence it moves the declarations to the top of the relevant scope. So you have to be careful if you start using the var keyword, and also pay attention to when you use function and function declarations. Now though declarations are hoisted, assignments are not, and that includes function expressions, which can create some other types of errors. We'll take a look at some examples in just a minute. Because of the way that JavaScript handles scope, hoisting can create other…
Contents
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How do you use the data- attribute in HTML?11m 14s
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Are you comfortable using jQuery?11m 32s
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Describe when you should use the bind() method5m 21s
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Do you know how to use the conditional operator?3m 43s
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Have you used Ajax to load an external file?8m 25s
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Have you used JavaScript templates?7m 3s
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How do you manipulate the DOM?11m 7s
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How do you use a constructor to create instances?10m 33s
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How do you use arrow functions in ES6?6m 30s
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How do you use the Fetch API?7m 22s
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How do you render JSON to a DOM element?9m 36s
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How does an IIFE work?7m 12s
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How does immutability work in JavaScript?4m 12s
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How would you use JavaScript reduce()?3m 54s
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Quick concepts: Do you have experience linting your code?2m 31s
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What are event bubbling and propagation about?11m 42s
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What does "use strict" do?3m 28s
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What is a callback and how do you use it?8m 51s
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What is the relationship between promises and callbacks?9m 57s
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What is the virtual DOM?7m 7s
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What is variable hoisting and how do you guard against it?8m 43s
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What tooling options have you used in the past?7m 11s
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When would you use recursion?6m 25s
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Can you build a Sass mixin?7m 57s
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Do you know how to use CSS variables?10m 38s
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How do you animate CSS?9m 41s
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How do you debug CSS using your browser?10m 47s
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How do you use calc() in CSS?9m 56s
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How does routing work in a modern web application?9m 30s
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