What are the language types of javaScript?

JavaScript is a dynamic language, and the compiler can only detect language errors during execution, not during compilation. At the same time, JavaScript is also an interpreted language. It does not need to compile the code into executable binary code first, but interprets the code line by line during the execution process.

In JavaScript, there are the following language types:

1. Undefined type

The Undefined type means that the variable is undefined or unassigned, and it has only one The value is undefined. For example:

var a;
console.log(a); // undefined

2. Null type

The Null type indicates that the variable value is empty, and it has only one value, null. For example:

var b = null;
console.log(b); // null

3. Boolean type

The Boolean type has only two values: true and false, used to represent logical results. For example:

var x = 1;
var y = 2;
var z = x > y;
console.log(z); // false

4. Number type

The Number type is used to represent numerical values, including integers, floating point numbers, NaN (Not a Number), etc. For example:

var i = 123;
var j = 3.14;
var k = NaN;
console.log(i, j, k); // 123, 3.14, NaN

5. String type

String type is used to represent text strings. The characters in the string can be any characters, including letters, numbers, symbols, and spaces. wait. For example:

var str = "Hello, JavaScript!";
console.log(str); // Hello, JavaScript!

6. Object type

The Object type is a special type used to represent a collection of related properties and methods. It is a reference type that can contain any type of value. For example:

var obj = {
  name: "Tom",
  age: 20,
  job: "Developer"
};
console.log(obj.name, obj.age, obj.job); // Tom, 20, Developer

7. Array type

The Array type represents an ordered collection, and each element can be of any type. It is a special object type with some common properties and methods, such as pop(), push(), shift(), and unshift(). For example:

var arr = [1, 2, 3];
console.log(arr[0], arr[1], arr[2]); // 1, 2, 3

8. Function type

Function type represents a function, which can be defined, called, passed parameters and return values. Functions are one of the basic building blocks in JavaScript, used for code reuse and abstraction. For example:

function add(x, y) {
  return x + y;
}

var result = add(1, 2);
console.log(result); // 3

The above are the common language types in JavaScript. Each type has its own characteristics and uses. Programmers can choose and use them according to specific situations.

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