That's why we use another !. Basically, !! makes us sure the value we get is Boolean, not falsy, truthy, string, etc... So it's like using the Boolean function in JavaScript, but an easier and …

Sep 17, 2011 · When it does just follow the links to the first time the question was asked and you should find the info you're looking for. The !! ensures the resulting type is a boolean (true or …

Mar 28, 2015 · ! is the logical negation or "not" operator. !! is ! twice. It's a way of casting a "truthy" or "falsy" value to true or false, respectively. Given a boolean, ! will negate the value, i.e. !true …

Oct 13, 2025 · Welcome to the MDN beginner's JavaScript course! In this article we will look at JavaScript from a high level, answering questions such as "What is it?" and "What can you do …

Mar 20, 2024 · A practical guide to understanding what !! does in JavaScript, with real examples you can use in your code today.

Aug 5, 2025 · Arrow functions are a shorthand syntax for writing functions in JavaScript, using the => operator. They offer a more concise way to express functions, especially for single …

Learn all about the JavaScript double exclamation mark operator (!!) with this comprehensive guide. Includes examples and explanations of how to use it, along with common pitfalls to avoid.

Aug 8, 2022 · Modern JavaScript is a “safe” programming language. It does not provide low-level access to memory or the CPU, because it was initially created for browsers which do not …

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Jul 8, 2025 · Expressions and operators Previous Next This chapter describes JavaScript's expressions and operators, including assignment, comparison, arithmetic, bitwise, logical, …