Method with parameters in javascript

Creating a JavaScript function with parameters for a personalized object

The code above defines an object with properties such as firstName, lastName, age, and eyeColor, as well as a method called fullName. Methods are essentially functions that are stored as object properties. The goal is to use objects to have constant access to these methods, rather than just in specific cases, as demonstrated in the code snippets above.

JavaScript Object Methods

Example

const person = <
firstName: «John»,
lastName: «Doe»,
id: 5566,
fullName: function() <
return this .firstName + » » + this .lastName;
>
>;

What is this ?

In the world of JavaScript, converting this to an object can be achieved using keyword refers .

The object being used or called is dependent on the way this is invoked.

The meaning of the this keyword varies depending on its usage and can refer to various objects.

Within a method of an object, the identifier this is used to denote the same object.

When used in isolation, this pertains to the worldwide entity known as the global object.

Within a function, the reference this points towards the global object.

Within a strict mode function, the state of this is defined as undefined .

At an occurrence, the element which received the event is denoted by this .

There are various techniques such as call() , apply() , and bind() that can be used to refer to any object with the help of this .

Note

See Also:

A Tutorial on the Use of ‘this’ in JavaScript

JavaScript Methods

Objects can undergo operations.

A function definition is contained in a property referred to as a method in JavaScript.

Property	Value
firstName	John
lastName	Doe
age	50
eyeColor	blue
fullName	A code block that concatenates the values of «firstName» and «lastName» properties and returns the result.

Functions that are saved as object properties are referred to as methods.

Accessing Object Methods

To gain entry to an object method , utilize the subsequent syntax:

It is common to refer to fullName() as a method belonging to the person object, while fullName is identified as a property.

When the () is used to call it, the fullName property will be executed as a function.

This instance utilizes the person object’s fullName() method.

Example

The function definition will be returned if the fullName property is accessed without using ().

Example

Adding a Method to an Object

Example

Using Built-In Methods

Here, the String object’s toUpperCase() method is utilized to convert a given text into uppercase.

What will be the resulting value of x once the code above is executed?

Example

Javascript function with condition in parameter Code, javascript function with condition in parameter. javascript by The Amateur on Apr 01 2020 Comment. 0. xxxxxxxxxx. 1. function myFuntionName(condition) <. 2. //this example uses an if statement. 3.

How do you create a method with parameters for a custom object in JavaScript?

Despite being highly skilled in computers, I’m facing an unresolved issue with building a javascript object. This particular problem has left me frustrated, as I am working with three external js FILE sources and an HTML file that triggers the call.

var URLDisectorO=< function URLDisector(URL)< //HERE THE COMPILER SAYS: Unexpected identifier Uncaught ReferenceError: //I need to pass a URL into this from another function. //test if the URL has google search in it var myURL = "" + URL; var index = mySearch(myURL, "https://www.google.com/search?q="); if(index==-1)< document.getElementById('currentLink').innerHTML = myURL + "

This URL WON'T be blocked!"; > else< if(index==0)< document.getElementById('currentLink').innerHTML = myURL + "

This URL WILL be blocked!"; > else < return "ERROR"; >> > function mySearch(str, str1)< //Searches the URL for the two strings passed in. var index=-1; var strlength=str.length; var str1length=str1.length; var length=0; if(strlength>str1length) < length=str1length; >else length=strlength; for(var i=0; iindex && index==-1 && i <1)< index=i; >for(var j=i; j else < index="-1;" break; >> end of inner for loop if(index="=-1) > > end of outer for loop if(index>0) < return -1; >else < return index; >>//end my search method > 

The JavaScript file named «popup» includes a test labeled as Object Methods , followed by a colon and File Code .

//This is the file doing the calling and passing in stuff to the other file above. //The HTML file called the JS file and it starts and it works until it gets down to. var txtU=""; function getURL()< chrome.tabs.getSelected(null, function(tab) < var URL=""; document.getElementById('currentLink').innerHTML = tab.url; URL = "" + document.getElementById('currentLink').innerHTML; txtU+=URL; alert("The URL is:\n\n" + txtU); URLDisectorO.URLDisector(txtU); //Object Call Here! //HERE THIS DOESN'T WORK. //The compiler says: Uncaught SyntaxError: URLDisectorO is not defined. >); > getURL();//The Call! The main method's call! 

What concerns me is the appearance of a popup. Specifically, the code functions properly only when it is the sole piece of code present and when it is included in the HTML file.

var txtU=""; function getURL()< chrome.tabs.getSelected(null, function(tab) < var URL=""; document.getElementById('currentLink').innerHTML = tab.url; URL = "" + document.getElementById('currentLink').innerHTML; txtU+=URL; alert("The URL is:\n\n" + txtU); URLDisector(txtU); >); > getURL();//The Call! The main method's call! function URLDisector(URL)< var myURL = "" + URL; var index = mySearch(myURL, "https://www.google.com/search?q="); if(index==-1)< document.getElementById('currentLink').innerHTML = myURL + "

This URL WON'T be blocked!"; > else< if(index==0)< document.getElementById('currentLink').innerHTML = myURL + "

This URL WILL be blocked!"; > else < return "ERROR"; >> > function mySearch(str, str1)< var index=-1; var strlength=str.length; var str1length=str1.length; var length=0; if(strlength>str1length) < length=str1length; >else length=strlength; for(var i=0; iindex && index==-1 && i <1)< index=i; >for(var j=i; j else < index="-1;" break; >> end of inner for loop if(index="=-1) > > end of outer for loop if(index>0) < return -1; >else < return index; >>//end of method 

I prefer using objects as they provide access to methods on a continuous basis rather than in a specific case. This would enhance the code’s flexibility, allowing me to call them whenever necessary (as seen in SETUP 1 — popup (Object Methods test).js). Nevertheless, I aim to maintain the existing setup and avoid resorting to the one below.

I would highly appreciate any guidance or instructions provided to fix the error.

As Sam I am mentioned, you have shared too much information and I’m unable to comprehend your issue. Nonetheless, it seems that the order of js files in the html file is incorrect. You may want to attempt the following approach:

Dedicate a few moments to refining your question by making it more concise and comprehensible.

For your web application based on JavaScript, it is advisable to employ an improved design pattern. It would be helpful for you to refer to Douglas Crockford’s book, JavaScript: The Good Parts.

Keeping a global object that saves reference to methods can be considered a makeshift solution, but it is not advisable to use it in the long term.

var foo = function () < alert("hello world"); >; var globalContext = < fooMethod : foo, >; 

By using globalContext.fooMethod(); , you can now access the <> stored in JavaScript create objects . This storage contains key->value pairs, where the values can be various types including methods.

With the aid of HUGO’s feedback on Attach get/set function to objects property in js , I gained clarity on the necessary steps to take.

Initially, my task was to assign a function to a variable. This function would serve as an encapsulating structure for an object, which I needed to create in a separate class. With this object instance, I could easily access its methods and variables. Please excuse me if my vocabulary usage is incorrect, but my intentions are good.

Examine the code to identify the dissimilarities. The comments will offer guidance and explain the reasoning for the changes made.

var global=function()< //The declaration of a global variable set to a function object value. var URL=""; this.URLD=function URLDisector(URL)< //This is different. /*With this in front of the property name. this displays the correct format of how to include a function as a property of the Object. *The correct way to call a method inside this object is: * *this.propertyName(parameter); OR this.propertyName(); * *Though a correct declaration of this looks like: * *this.URLD=function URLDisector(URL)< *. code inside the method. *>; */ var myURL = "" + URL; var index = this.search(myURL, "https://www.google.com/search?q="); //This is different. if(index==-1)< document.getElementById('currentLink').innerHTML = myURL + "

This URL WON'T be blocked!"; > else< if(index==0)< document.getElementById('currentLink').innerHTML = myURL + "

This URL WILL be blocked!"; > else < return "ERROR"; >> > //end first inside Function this.search=function mySearch(str, str1)< //This is different. var index=-1; var strlength=str.length; var str1length=str1.length; var length=0; if(strlength>str1length) < length=str1length; >else length=strlength; for(var i=0; iindex && index==-1 && i <1)< index=i; >for(var j=i; j else < index="-1;" break; >> end of inner for loop if(index="=-1) > > end of outer for loop if(index>0) < return -1; >else < return index; >> //end my search method >; 

Code written in the FILE named popup (Object Methods test).js.

var txtU=""; var g = new global(); /*This is different. This line declares that: We have an object with the instance name "g" "g" contains the properties found inside the object or class called "global".*/ function getURL()< chrome.tabs.getSelected(null, function(tab) < var URL=""; document.getElementById('currentLink').innerHTML = tab.url; URL = "" + document.getElementById('currentLink').innerHTML; txtU+=URL; alert("The URL is:\n\n" + txtU); g.URLD(txtU); /*This is different. *This line says that we want to call the object name and, in this case, *call the method property name "URLD" and pass in "txtU" as the parameter to it. >); > getURL(); //The Call! The main method's call! 

Out parameters — How best to implement out params in, What this example does is it uses the result parameter to pass an error message as follows: errorObj.value = «ODP failed test foo»; // return error If you run the example it will display this message in a popup dialog.

Javascript pass object method as parameter

js pass object property as a function parameter

let a = < foo: 123 >; a.foo // 123 a['foo'] // 123 let str = 'foo'; a[str] // 123

In, /// OBJECTS IN JAVASCRIPT const testScore = < damon: 89, shawn: 91, keenan: 80, kim: 89, >; Object.keys(testScore); // gives all keys Object.values(testScore); // gives all values Object.entries(testScore); // gives nested arrays of key-value pairs // YOU CAN USE ( FOR-IN ) LOOP FOR ITERATION OVER OBJECTS for (let person in …

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JavaScript Function Parameters

A JavaScript function does not perform any checking on parameter values (arguments).

Function Parameters and Arguments

Earlier in this tutorial, you learned that functions can have parameters:

Function parameters are the names listed in the function definition.

Function arguments are the real values passed to (and received by) the function.

Parameter Rules

JavaScript function definitions do not specify data types for parameters.

JavaScript functions do not perform type checking on the passed arguments.

JavaScript functions do not check the number of arguments received.

Default Parameters

If a function is called with missing arguments (less than declared), the missing values are set to undefined .

Sometimes this is acceptable, but sometimes it is better to assign a default value to the parameter:

Example

Default Parameter Values

ES6 allows function parameters to have default values.

Example

If y is not passed or undefined, then y = 10.

Function Rest Parameter

The rest parameter (. ) allows a function to treat an indefinite number of arguments as an array:

Example

function sum(. args) <
let sum = 0;
for (let arg of args) sum += arg;
return sum;
>

let x = sum(4, 9, 16, 25, 29, 100, 66, 77);

The Arguments Object

JavaScript functions have a built-in object called the arguments object.

The argument object contains an array of the arguments used when the function was called (invoked).

This way you can simply use a function to find (for instance) the highest value in a list of numbers:

Example

x = findMax(1, 123, 500, 115, 44, 88);

function findMax() let max = -Infinity;
for (let i = 0; i < arguments.length; i++) if (arguments[i] > max) max = arguments[i];
>
>
return max;
>

Or create a function to sum all input values:

Example

x = sumAll(1, 123, 500, 115, 44, 88);

function sumAll() let sum = 0;
for (let i = 0; i < arguments.length; i++) sum += arguments[i];
>
return sum;
>

If a function is called with too many arguments (more than declared), these arguments can be reached using the arguments object.

Arguments are Passed by Value

The parameters, in a function call, are the function’s arguments.

JavaScript arguments are passed by value: The function only gets to know the values, not the argument’s locations.

If a function changes an argument’s value, it does not change the parameter’s original value.

Changes to arguments are not visible (reflected) outside the function.

Objects are Passed by Reference

In JavaScript, object references are values.

Because of this, objects will behave like they are passed by reference:

If a function changes an object property, it changes the original value.

Changes to object properties are visible (reflected) outside the function.

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