What is the most efficient approach to save a value for future utilization in a subsequent function? I've heard that exploiting global variables is highly unfavorable

Question

What is the most efficient approach to save a value for future utilization in a subsequent function? I've heard that exploiting global variables is highly unfavorable

So I have this code that can be found at http://jsfiddle.net/8j947/10/. It returns either true or false for the variable isLive. My main concern now is how to utilize the variable onLive in a subsequent function. While I've encountered some solutions on this StackOverflow thread, I'm struggling to make it work effectively. All I really need is to preserve the value of isLive, so that I can employ it within an if statement later on. Is there a straightforward approach that anyone can suggest? Is it possible to store the data as an object?

javascript jquery global-variables store

Answer 1

Answer №1

If you find yourself in a situation where your functions rely on certain variables, it's best to define those variables within the same scope as the functions themselves. For example, if your functions exist in the global scope, then the variables they depend on should also be globally scoped.

However, if you're working on something like a plugin, control, or script that will be used across multiple pages, it's generally recommended to avoid using global variables. Instead, consider finding alternative ways to pass necessary data between different locations.

That being said, there are exceptions to every rule. Sometimes, understanding the rules allows you to know when and how to break them effectively.

If you suddenly realize that your functions are all in the global scope and you'd like to change that, there is a solution. Wrap your entire code within an anonymous function and immediately call it:

(function(){
    var variableScopedToFunction = true;
    function functionScopedToParent(){
        ...
    }
    window.globalVariableAvailableAcrossScopes = "foo";
    window.globalFunctionAvailableAcrossScopes = function(){
        ...
    };
})();

Answer 2

If you find yourself in a situation where your functions rely on certain variables, it's best to define those variables within the same scope as the functions themselves. For example, if your functions exist in the global scope, then the variables they depend on should also be globally scoped.

However, if you're working on something like a plugin, control, or script that will be used across multiple pages, it's generally recommended to avoid using global variables. Instead, consider finding alternative ways to pass necessary data between different locations.

That being said, there are exceptions to every rule. Sometimes, understanding the rules allows you to know when and how to break them effectively.

If you suddenly realize that your functions are all in the global scope and you'd like to change that, there is a solution. Wrap your entire code within an anonymous function and immediately call it:

(function(){
    var variableScopedToFunction = true;
    function functionScopedToParent(){
        ...
    }
    window.globalVariableAvailableAcrossScopes = "foo";
    window.globalFunctionAvailableAcrossScopes = function(){
        ...
    };
})();

Answer 3

Answer №2

Using global variables can be problematic as they allow any function to potentially modify the variable, leading to difficult-to-trace bugs. Although this may not pose significant issues for simple projects, it is crucial to consider the implications.

To mitigate the risks associated with polluting the global namespace and minimize the chance of encountering the above-mentioned bugs, an alternative approach is creating a distinct "namespace" object (Option 2 from the linked question's accepted answer). Here's an example:

var MyDataStore = {};

MyDataStore.someProperty = someFunction();

// Later on...

function anotherFunction() {
    // Access the data you previously stored...
    alert(MyDataStore.someProperty);
}

Answer 4

Using global variables can be problematic as they allow any function to potentially modify the variable, leading to difficult-to-trace bugs. Although this may not pose significant issues for simple projects, it is crucial to consider the implications.

To mitigate the risks associated with polluting the global namespace and minimize the chance of encountering the above-mentioned bugs, an alternative approach is creating a distinct "namespace" object (Option 2 from the linked question's accepted answer). Here's an example:

var MyDataStore = {};

MyDataStore.someProperty = someFunction();

// Later on...

function anotherFunction() {
    // Access the data you previously stored...
    alert(MyDataStore.someProperty);
}

Answer 5

Answer №3

I don't believe that global variables are inherently bad, but it is crucial to take certain precautions when utilizing them.

To prevent conflicts with other global variables, especially those from external libraries, I suggest implementing two measures:

1) Utilize self-invoking anonymous functions to encapsulate your code and isolate the variables within.

// Code from other developers or modules
var myVariable = "whatever";

// Anonymous function for your self-contained code
(function(){
    var myVariable = "inside closure";
    alert(myVariable);
})() // The empty brackets invoke the anonymous function

// Still retains the value from before your self-invoking anonymous function
alert(myVariable);

2) Create a unique namespace and place all of your global variables under that namespace to avoid polluting the global scope.

myUniqueNamespaceRaiders = {};
// This will not conflict with other global variables as long as your namespace is distinct
myUniqueNamespaceRaiders.desiredVariable = "something";

In my opinion, if you organize your global variables properly, it is acceptable to use them. My hope is that this information proves helpful to you.

Answer 6

I don't believe that global variables are inherently bad, but it is crucial to take certain precautions when utilizing them.

To prevent conflicts with other global variables, especially those from external libraries, I suggest implementing two measures:

1) Utilize self-invoking anonymous functions to encapsulate your code and isolate the variables within.

// Code from other developers or modules
var myVariable = "whatever";

// Anonymous function for your self-contained code
(function(){
    var myVariable = "inside closure";
    alert(myVariable);
})() // The empty brackets invoke the anonymous function

// Still retains the value from before your self-invoking anonymous function
alert(myVariable);

2) Create a unique namespace and place all of your global variables under that namespace to avoid polluting the global scope.

myUniqueNamespaceRaiders = {};
// This will not conflict with other global variables as long as your namespace is distinct
myUniqueNamespaceRaiders.desiredVariable = "something";

In my opinion, if you organize your global variables properly, it is acceptable to use them. My hope is that this information proves helpful to you.

Answer 7

Answer №4

If there is a specific set of functions and data you are dealing with, an alternative approach would be as follows:

const customInterface = function(){
   let isOnline = false;

   this.method1(){ isOnline = true };
   this.method2(){ console.log( isOnline ) };
};

By using this method, method1 and method2 can share relevant data without unnecessarily cluttering the global namespace.

For a practical example, please refer to: http://jsfiddle.net/XpJFn/1/

Answer 8

If there is a specific set of functions and data you are dealing with, an alternative approach would be as follows:

const customInterface = function(){
   let isOnline = false;

   this.method1(){ isOnline = true };
   this.method2(){ console.log( isOnline ) };
};

By using this method, method1 and method2 can share relevant data without unnecessarily cluttering the global namespace.

For a practical example, please refer to: http://jsfiddle.net/XpJFn/1/

Answer 9

Answer №5

Consider incorporating modular programming techniques in your JavaScript code.

In addition, using closures can be beneficial for encapsulating data without polluting the global scope.

If you find it necessary to use a global variable, it's recommended to create your own dedicated namespace and place any required variables or functions within that context.

For example:

// Custom Global Namespace
window.myNamespace = {};

myNamespace.isOnLiveMode = false;

// Using closures
var hello = (function() {

  var onLive = true;

  return {
    fn1: function () {
      return onLive;
    },
    fn2: function () {
      return !onLive;
    }
  };
})();

hello.fn1(); // returns true
hello.fn2(); // returns false

Answer 10

Consider incorporating modular programming techniques in your JavaScript code.

In addition, using closures can be beneficial for encapsulating data without polluting the global scope.

If you find it necessary to use a global variable, it's recommended to create your own dedicated namespace and place any required variables or functions within that context.

For example:

// Custom Global Namespace
window.myNamespace = {};

myNamespace.isOnLiveMode = false;

// Using closures
var hello = (function() {

  var onLive = true;

  return {
    fn1: function () {
      return onLive;
    },
    fn2: function () {
      return !onLive;
    }
  };
})();

hello.fn1(); // returns true
hello.fn2(); // returns false

Answer 11

Answer №6

It would be beneficial for you to check out the concept of localStorage. You can find more information about it at .

Answer 12

It would be beneficial for you to check out the concept of localStorage. You can find more information about it at .

Answer 13

Answer №7

In case you strongly prefer not to utilize global variables, an alternative option could be creating a function that retrieves the variable value.

retrieveVariable = function(){
    return "Greetings!";
}

It's important to note that global variables aren't inherently malevolent; their usage should simply align with your specific requirements. If there is a valid reason for employing a global variable, it is perfectly acceptable to do so.

Answer 14

In case you strongly prefer not to utilize global variables, an alternative option could be creating a function that retrieves the variable value.

retrieveVariable = function(){
    return "Greetings!";
}

It's important to note that global variables aren't inherently malevolent; their usage should simply align with your specific requirements. If there is a valid reason for employing a global variable, it is perfectly acceptable to do so.

What is the most efficient approach to save a value for future utilization in a subsequent function? I've heard that exploiting global variables is highly unfavorable

Answer №1

Answer №2

Answer №3

Answer №4

Answer №5

Answer №6

Answer №7

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