operatorwould be truthy in nature resulting inFALSE. -1 is special because ~(-1) gives 0 which is falsy in JavaScript. Adding the! operatorgives us the onlyTRUE. When to use this special case ? A lot of times in JavaScript String manipulation, you are required to search for a particular...
Bookmarkletsare URLs with JavaScript programs that are "executed in the address bar". If a bookmarklet returns a result that is notundefined, the content of the currently shown web page is replaced with it. It is such a perfect use case for thevoidoperator. Compare [This difference only exis...
false Here, thedouble negation/double not not (!!) operatorcalculates thetruthvalue of a value. It returns a Boolean value. JavaScript Examples »
Sometimes we might want to make a function more generic by having it accept a union of different types as an argument. Using the JavaScript “in” operator, we can test for the presence of different properties on the argument object, and TypeScript will automatically infer the exact type of ...
In JavaScript, a common way to coerce any value into a boolean is to apply the logical NOT operator!twice: functionisAdministrator(user) {return!!(user&&user.isAdmin);} The!operator, produces the valuefalseif its single operand can be coerced intotrue; otherwise, it returnstrue. The result...
This operator is essential in JavaScript as a variable is dynamically typed. By using typeof, you can use JavaScript to return the data type as a string. You can then use this string to check whether the variable is in the expected type. ...
(not not) operator in JavaScript? 解答1 Coerces强制oObjectto boolean. If it was falsey (e.g. 0,null,undefined, etc.), it will befalse, otherwise,true. !oObject //Inverted boolean !!oObject //Non inverted boolean so true boolean representation ...
Learn the basics of the JavaScript `in` OperatorTHE AHA STACK MASTERCLASS Launching May 27th The in operator is pretty useful. It allows us to check if an object has a property.This operator returns true if the first operand is a property of the object passed on the right, or a ...
In this article, we will learn about the !! (not not) operator inJavaScript.This double negation forces a value to be evaluated as either true or false. What is the !! Operator? The double negation(!! )operatoris the! Operator twice and calculates the truth value of a value. It retur...
The spread operator in JavaScript is a syntax introduced in ECMAScript 6 (ES6) that allows you to spread the elements of an iterable (such as arrays, strings, or objects), into another iterable or function call.It is denoted by three dots “...” followed by an expression or an ...