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  1. javascript - When should I use ?? (nullish coalescing) vs || (logical ...

    ) in JavaScript only considers null or undefined as "nullish" values. If the left-hand side is any other value, even falsy values like "" (empty string), 0 , or false , it will not use the right-hand side:

  2. Which equals operator (== vs ===) should be used in JavaScript ...

    Dec 11, 2008 · JavaScript has two sets of equality operators: === and !==, and their evil twins == and !=. The good ones work the way you would expect. The good ones work the way you would expect. If the two operands are of the same type and have the same value, then === produces true and !== produces false .

  3. What does the !! (double exclamation mark) operator do in …

    A third use is to produce logical XOR and logical XNOR. In both C and JavaScript, a && b performs a logical AND (true if both sides are true), and a & b performs a bitwise AND. a || b performs a logical OR (true if at least one are true), and a | b performs a bitwise OR.

  4. How do you use the ? : (conditional) operator in JavaScript?

    Jun 7, 2011 · It's a little hard to google when all you have are symbols ;) The terms to use are "JavaScript conditional operator". If you see any more funny symbols in JavaScript, you should try looking up JavaScript's operators first: Mozilla Developer Center's list of operators. The one exception you're likely to encounter is the $ symbol.

  5. What's the difference between & and && in JavaScript?

    This operator is almost never used in JavaScript. Other programming languages (like C and Java) use it for performance reasons or to work with binary data. In JavaScript, it has questionable performance, and we rarely work with binary data. This operator expects two numbers and returns a number. In case they are not numbers, they are cast to ...

  6. What is the purpose of the dollar sign in JavaScript?

    Mar 29, 2022 · Unlike many similar languages, identifiers (such as functional and variable names) in Javascript can contain not only letters, numbers and underscores, but can also contain dollar signs. They are even allowed to start with a dollar sign, or consist only of a dollar sign and nothing else. Thus, $ is a valid function or variable name in Javascript.

  7. What does ${} (dollar sign and curly braces) mean in a string in ...

    Mar 7, 2016 · I haven't seen anything here or on MDN. I'm sure I'm just missing something. There's got to be some documentation on this somewhere.

  8. Difference between == and === in JavaScript - Stack Overflow

    Feb 7, 2009 · JavaScript has both strict and type-converting equality comparison. For strict equality the objects being compared must have the same type and: Two strings are strictly equal when they have the same sequence of characters, same length, and same characters in corresponding positions.

  9. Is there a "null coalescing" operator in JavaScript?

    Jan 25, 2009 · After reading your clarification, @Ates Goral's answer provides how to perform the same operation you're doing in C# in JavaScript. @Gumbo's answer provides the best way to check for null; however, it's important to note the difference in == versus === in JavaScript especially when it comes to issues of checking for undefined and/or null.

  10. How to use OR condition in a JavaScript IF statement?

    Jan 11, 2023 · In JavaScript, if you're looking for A or B, but not both, you'll need to do something similar to:

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