The JavaScript function is a set of statements that take inputs, do some specific computation, and produce output. Basically, a function is a set of statements that performs some tasks or does some computation and then return the result to the user.
Syntax:
function functionName(Parameter1, Parameter2, ..) {
// Function body
}
Example: Below is a sample program that illustrates the working of functions in JavaScript:
Javascript
// Function definition function welcomeMsg(name) { console.log("Hello " + name + " welcome to neveropen"); } // creating a variable let nameVal = "Admin"; // calling the function welcomeMsg(nameVal); |
Output:
Hello Admin welcome to neveropen
The Complete List of JavaScript Functions & Properties are listed below:
JavaScript Function Parameters:
|
Parameters |
Description |
Example |
|---|---|---|
| Function | The function definition and real values passed to the function in the function definition are known as arguments. | |
| Rest | Improved way to handle function parameters defined, allowing us to more easily handle various inputs as parameters in a function. | |
| Default parameters | In JavaScript, the parameters of functions default to undefined. However, in some situations, it might be useful to set a different default value. |
JavaScript Functions Properties:
|
Properties |
Description |
Example |
|---|---|---|
| length | Return the number of parameters required by a function. | |
| displayName | Set the display name of the function. | |
| caller | Returns the function that invoked the specified function. | |
| name | Return the name of the function. |
JavaScript Functions:
|
Functions |
Description |
Example |
|---|---|---|
| apply() | It is different from the function call() because it takes arguments as an array. | |
| isFinite() | It returns true for all the values except +infinity, -infinity, or NaN. | |
| isNaN() | It returns true if the value is a NaN else returns false. | |
| unescape() | It decodes that string encoded by the escape() function. | |
| escape() | It can be transmitted to any computer in any network which supports ASCII characters. | |
| number() | Convert the data type to a number. | |
| map() | The calling function for each and every array element in an array. | |
| String() | Convert the value of an object to a string value. | |
| eval() | If the argument represents one or more JavaScript statements, eval() evaluates the statements. | |
| uneval() | Create a string representation of the source code of an Object. | |
| parseInt() | Accept the string and radix parameters and convert them into an integer. | |
| parseFloat() | Accept the string and convert it into a floating-point number. | |
| console.log() | To print any kind of variables defined before in it or to just print any message that needs to be displayed to the user. |
Basics of Functions:
|
JavaScript Operations on Function |
Description |
Example |
|---|---|---|
| Function Generator | It needs to generate a value, it does so with the yield keyword rather than return. | |
| Function Binding | In JavaScript, function binding happens using bind() method. | |
| Function Invocation | It is common to use the term “call a function” instead of “invoke a function”. | |
| Function Expression | Create an anonymous function that doesn’t have any function name. | |
| Arrow Functions | Provide generator functions with a concise way to write functions in JavaScript. | |
| Async Function | It checks that we are not breaking the execution thread. | |
| Pure Functions | Returns the same result if the same arguments are passed. | |
| Nested Functions | Return is a combination of the output from the outer as well as the inner function(nested function). |
