What is not an array method in JavaScript?

JavaScript is a programming language widely used in web development. It has numerous built-in methods and functions, among which array methods are the most commonly used part of JavaScript programming, because when developing websites and other web applications, we often need to operate on data. However, there are certain built-in functions that are not array methods. In this article, we will discuss functions in JavaScript that are not array methods.

1. isNaN()

The isNaN() function is used to check whether a value is a non-numeric value. It's a global function in JavaScript, not an array method. Its syntax is as follows:

isNaN(value)

where value is the value to be checked. If value is a number, isNaN() will return false. If value is a non-number, return true.

2. parseFloat()

The parseFloat() function parses a string into a floating point number and returns the result. It's also not an array method. The syntax is as follows:

parseFloat(string)

where string is the string to be parsed. If the string can be parsed as a floating point number, parseFloat() will return that value, otherwise it will return NaN.

3. parseInt()

The parseInt() function parses a string into an integer and returns the result. It's also not an array method. The syntax is as follows:

parseInt(string, radix)

where string is the string to be parsed, and radix is ​​a base number between 2 and 36, indicating the base used when parsing string. If radix is ​​omitted, the default value is 10. If the string can be parsed as an integer, parseInt() will return that value, otherwise it will return NaN.

4. isFinite()

The isFinite() function is used to check whether a value is a finite value. It's also not an array method. The syntax is as follows:

isFinite(value)

where value is the value to be checked. If value is a finite value, isFinite() will return true, otherwise it will return false.

5. eval()

The eval() function is used to execute a piece of JavaScript code and return the execution result. It's also not an array method. The syntax is as follows:

eval(code)

where code is the JavaScript code to be executed. The eval() function can execute any valid JavaScript statement, including defining variables, declaring functions, performing operations, etc. However, it is also easily abused as it can execute any code, including malicious code.

In JavaScript programming, array methods are an extremely important part. However, it should be noted that not all built-in functions are array methods. In actual development, we need to choose appropriate functions and methods based on actual needs to ensure the correctness and efficiency of the program.

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