What types are there in javascript

In JavaScript, variables can store different types of data, including numbers, strings, Boolean values, arrays, objects, etc. The following are the main types in JavaScript:

1. Number types

Number types include integers and floating point numbers. Integers are numbers without a decimal point, such as 1, 2, 3, etc. Floating point numbers are numbers with a decimal point, such as 1.2, 3.14, etc.

2. String type

The string type is a sequence of zero or more characters. You can use single or double quotes to enclose strings, such as 'hello', "world", etc.

3. Boolean type

The Boolean type has only two values: true and false. Boolean types are usually used in conditional statements, such as if statements, while statements, etc.

4. Array type

The array type can store a set of ordered data, which can be numbers, strings, Boolean values, etc. You can use square brackets [] to create an array, such as [1, 2, 3], ['apple', 'banana', 'orange'], etc.

5. Object type

The object type is the most important type in JavaScript. Objects can be used to represent a set of related values ​​and methods, such as a person's name, age, gender and other attributes, as well as some behaviors the person has, such as walking, talking, etc. You can use curly braces {} to create an object, for example {name: 'Jack', age: 18, gender: 'male'}.

6. null and undefined

null and undefined usually indicate that a variable has no value. null means that the variable is assigned a value of null, and undefined means that the variable is not assigned a value.

7. Function type

The function type is a special object type that can be used to encapsulate a reusable block of code. Functions can receive multiple parameters, perform some operations, and return a value. You can use the function keyword to define a function, for example:

function add(a, b) {
  return a + b;
}

Summary

There are many data types in JavaScript, including numbers, strings, Boolean values, arrays, objects, null, and undefined and function types. According to different needs and scenarios, choose different data types to store and operate data. Proficiency in JavaScript data types is the foundation for writing high-quality code.

The above is the detailed content of What types are there in javascript. For more information, please follow other related articles on the PHP Chinese website!