How do you log a variable type in JavaScript?
How do you log a variable type in JavaScript?
Use the typeof operator to get the type of an object or variable in JavaScript. The typeof operator also returns the object type created with the “new” keyword. As you can see in the above example, the typeof operator returns different types for a literal string and a string object.
What are the 5 data types in JavaScript?
In Javascript, there are five basic, or primitive, types of data. The five most basic types of data are strings, numbers, booleans, undefined, and null. We refer to these as primitive data types.
What are 3 types of data in JavaScript?
JavaScript allows you to work with three primitive data types: numbers, strings of text (known as “strings”), and boolean truth values (known as “booleans”). JavaScript also defines two trivial data types, null and undefined, each of which defines only a single value.
What is typeof in JavaScript?
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.
How do you use typeof?
Real-world usage typeof is very useful, but it’s not as versatile as might be required. For example, typeof([]) , is ‘object’ , as well as typeof(new Date()) , typeof(/abc/) , etc. For checking non-existent variables that would otherwise throw a ReferenceError , use typeof nonExistentVar === ‘undefined’ .
What is Instanceof in JavaScript?
The instanceof operator tests to see if the prototype property of a constructor appears anywhere in the prototype chain of an object. The return value is a boolean value.
What are the 8 data types in JavaScript?
In this article, I will talk about 8 data types in that currently exist in JavaScript.
- String.
- Number.
- Boolean.
- Null.
- Undefined.
- Symbol.
- BigInt.
- Object.
What is the use of typeof ()?
The typeof operator is used to get the data type (returns a string) of its operand. The operand can be either a literal or a data structure such as a variable, a function, or an object. The operator returns the data type.
How many types of JavaScript are there?
JavaScript has seven built-in types: null , undefined , boolean , number , string , object , and symbol . They can be identified by the typeof operator.