passing variables across functions on javascript

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I'm trying to pass variables across functions, something like

function one() {
  var x = 1
}

function two() {
  var y = x + 1;
}

alert(y);

You will need to hoist the scope, by extracting the variable declaration to outside of the functions. That is to say, define x and y outside of the functions. Note that you can still update their values from within the functions. However, don't forget that you'll actually need to invoke both functions as well!

This can be seen in the following:

var x, y;

function one() {
   x = 1;
}

function two() {
  y = x + 1;
}

one();
two();
console.log(y);

How do i pass variables between functions in javascript, You will need to hoist the scope, by extracting the variable declaration to outside of the functions. That is to say, define x and y outside of the  Passing data is quite important in functional programming languages like JavaScript. When there are multiple functions (which is most of the time), there needs to be a way to pass data between the functions. This is done by passing values in parenthesis: myFunction(myData).

If you really want to get variable declared in one method, return it

  function one(){
        var x = 1;
        return x;
    }
    
    function two() {
      var x = one();
      var y = x + 1;
      return y;
    }
alert(two());

passing variables across functions on javascript, When there are multiple functions (which is most of the time), there needs to be a way This example only passes one variable to the function. Whereas JavaScript primitive variables are passed to functions by value, JavaScript objects are passed by reference. What this means is that if you pass an object as an argument to a function, any changes to that object within the function will also change the value outside of the function.

You current way has x and y in the scope of the function, which means the other function doesnt know it exists. Also, its good practice to name functions according to what they do. 3 straightforward ways to do this.

  1. Global
  2. Params
  3. Inline

  1. Set two variables outside of the functions scope that any function can reach.

var x, y;

function assignOne() {
   x = 1;
}

function addOne() {
  y = x + 1;
}

assignOne();
addOne();
console.log(y);

Ways of passing data to functions in JavaScript, Global JavaScript Variables. A variable declared outside a function, becomes GLOBAL. A global variable has global scope: All scripts and functions on a web  A variable declared inside a JavaScript function will only be local if you write it like this: function func(){ var x = 5; } However, if you don't use the var keyword, it will be added onto the window element, and thus global:

Seems like you want to have shared state between both functions instead of passing arguments. So, an object oriented pattern seems to be appropriate.

class Thing {
  constructor() {
    this.x = 1;
  }
  one() {
    return this.x;
  }
  two() {
    return this.x + 1;
  }
}

const t = new Thing();
console.log(t.one());
console.log(t.two());

JavaScript Scope, You can call a function by mentioning its name, followed by arguments in to a variable (as shown in the last example), passed as an argument to another function, but function declarations have two advantages over function expressions:. A JavaScript Function is a JavaScript Variable until it is executed (evaluated). Read on for a full explanation. JavaScript Functions as JavaScript Variables - DZone Web Dev

If you want to share variables between functions but don't want to declare them in global scope, you can use a closure like this:

(function() {
  var x, y;

  function one() {
    var x = 1
  }

  function two() {
    var y = x + 1;
  }
  one();
  two();
  alert(y);
})();

Chapter 15. Functions, This tutorial explains how JavaScript pass by value works and gives you some good knowledge of the primitive and reference values, and the differences between them. In JavaScript, all function arguments are always 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.

Understanding JavaScript Pass By Value, In this topic, you will learn how to use the JavaScript Module Design In the following code, the function and the variables exist within the scope of the page. walk backwards through the scope chain looking for a var statement With the anonymous function, you can explicitly pass in global parameters. Since local variables are only recognized inside their functions, variables with the same name can be used in different functions. Local variables are created when a function starts, and deleted when the function is completed.

Learn JavaScript - #13, We can pass arbitrary data to functions using parameters (also called If we want the returned expression to wrap across multiple lines, we  Variable names are case sensitive; JavaScript also has the convention of using camel case (sometimes stylized as camelCase) in the names of functions and variables declared with var or let. This is the practice of writing the first word lowercase, and then capitalizing the first letter of every subsequent word with no spaces between them.

The JavaScript Module Design Pattern, Remember that at this point, nothing has actually been done. The document.write statement actually triggers the function to run. But look! When the function is triggered to run, now it is being passed a new variable, "text". That's the text string of the location to be acted upon. The return is the text Super. Grab The Last Name

Comments
  • Please show us how you intend to call the functions. Without calling them, no assignment is done and no value is ever created.
  • Also please explain why you want/need to do this? Having function accept arguments and return values is a much better design.