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. For example, you can use typeof within a function where you need to perform a different action depending on the type of va...
If you do not wish to create a TypeScript environment on your local machine, you can use the officialTypeScript Playgroundto follow along. You will need sufficient knowledge of JavaScript, especially ES6+ syntax, such asdestructuring, rest operators, andimports/exports. If you need more informati...
Here, we have added the includes() method to the prototype of the string object. In the function, we throw the error if the search string is a type of regular expression. Also, the ‘pos’ parameter is an option, so if the user doesn’t pass it, consider it zero. At last, use ...
Thejest.mock()function will change the type of the dependency, because of which we need to use type casting after calling thejest.mock()function in TypeScript. We can easily call the type casting by using thetypeofmethod in TypeScript. ...
JavaScript, in turn, decides the data type of the variable, later, depending on the values assigned to these variables. It is seemingly easy to determine the data type of a variable. But some scenarios can put us in a fix. Especially in the case of values returned by the REST API ...
let str = `JavaScript Strings` console.log(str) // JavaScript Strings console.log(str.length) // 18 console.log(typeof str) // string You can also use single and double quotes in a template literal without escaping:let str = `What's up?` To escape a backtick in a template literal...
By usingString()orn.toString()we are able to explicitly convert values of Boolean ornumber data typesto string values in order to ensure that our code behaves as we anticipate. Converting Values to Numbers When converting values to a number data type, we’ll use theNumber()method. Primarily...
The best one in my opinion is to use the Number object, in a non-constructor context (without the new keyword):const count = Number('1234') //1234This takes care of the decimals as well.Number is a wrapper object that can perform many operations. If we use the constructor (new ...
Find out how to hash and check passwords in JavaScript with the bcrypt libraryThe bcrypt npm package is one of the most used packages to work with passwords in JavaScript.This is security 101, but it’s worth mentioning for new developers: you never store a password in plain text in the ...
This method is used to store key-value pair in the localstorage. Thekeyshould be a string, and the value should also be a string, or it can be a JavaScript object, which is automatically converted into a string, or you can use theJSON.stringifymethod for any custom object. ...