JavaScript typeof - W3Schools
WebJavaScript has 7 primitive data types: string. number. boolean. bigint. symbol. null. undefined. The typeof operator returns the type of a variable or an expression. Examples. typeof "John" // Returns string. typeof ("John"+"Doe") // Returns string. typeof 3.14 // Returns number. typeof 33 // Returns number. typeof (33 + 66) // Returns number.
typeof - JavaScript | MDN - MDN Web Docs
WebSep 12, 2023 · The typeof operator returns a string indicating the type of the operand's value. Try it. Syntax. js. typeof operand. Parameters. operand. An expression representing the object or primitive whose type is to be returned. Description. The following table summarizes the possible return values of typeof.
JavaScript TypeOf – How to Check the Type of a Variable or …
WebNov 9, 2020 · The typeof operator takes only one operand (a unary operator). It evaluates the type of the operand and returns the result as a string. Here is how you use it when you're evaluating the type of a number, 007. typeof 007; // returns 'number'.
Finding Variable Type in JavaScript - Stack Overflow
Web12 Answers. Sorted by: 306. Use typeof: > typeof "foo" "string" > typeof true. "boolean" > typeof 42. "number" So you can do: if(typeof bar === 'number') { //whatever. } Be careful though if you define these primitives with their object wrappers (which you should never do, use literals where ever possible): > typeof new Boolean(false) "object"
JavaScript typeof
WebThe following example shows how to use the typeof operator with values of various types: console .log(type); // 'string'. console .log(type); // 'number'. console .log(type); // 'bigint'. console .log(type); // 'boolean'. console .log(type); …
Type checking in JavaScript: typeof and instanceof operators
WebNov 24, 2020 · 1. typeof operator. In JavaScript, you can find primitive types like strings, numbers, booleans, symbols. Additionally, there are functions, objects, and the special values undefined and null. typeof is the operator that let's you determine the type of the expression: const typeAsString = typeof expression;
JavaScript typeof : Understanding type checking in JavaScript
WebSep 27, 2018 · JavaScript has a pretty basic typeof operator for the purpose of type checking. However, you will notice that using this operator could be misleading, as we will discuss in this article. JavaScript data types. Before looking at type checking with typeof, it is important to have a glance at the JavaScript data types.
JavaScript typeof Operator - Programiz
WebJavaScript typeof Operator. The typeof operator returns the type of variables and values. For example, const a = 9; console.log(typeof a); // number. console.log(typeof '9'); // string. console.log(typeof false); // boolean. Syntax of typeof Operator. The syntax of typeof operator is: typeof operand. Here, operand is a variable name or a value.
JavaScript Data Types: Typeof Explained - freeCodeCamp.org
WebDec 23, 2019 · typeof is a JavaScript keyword that will return the type of a variable when you call it. You can use this to validate function parameters or check if variables are defined. There are other uses as well. The typeof operator is useful because it is an easy way to check the type of a variable in your code.
typeof - MDN Web Docs
WebJava Script reference. Expressions and operators. typeof. Jump to: Syntax. Description. Examples. Additional information. Specifications. Browser compatibility. IE-specific notes. See also. The typeof operator returns a string indicating the type of the unevaluated operand. console.log(typeof 42); // expected output: "number"
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