How to retrieve the value of a variable from one JavaScript function and pass it to another

Question

How to retrieve the value of a variable from one JavaScript function and pass it to another

As a JavaScript beginner, I am looking for help in retrieving values from one function to another. Specifically, I would like to access the values of dinoRight, dinoLeft, and others in the cactus1move function.

const spawn = () => {
    const dinoRight = document.getElementById('dino').getBoundingClientRect().left + document.getElementById('dino').getBoundingClientRect().width;
    const dinoLeft = document.getElementById('dino').getBoundingClientRect().left; 
    const dinoHeight = document.getElementById('dino').getBoundingClientRect().height;
    const cactusTop = document.getElementById('cactus').getBoundingClientRect().top;
    const cactusWidth = document.getElementById('cactus').getBoundingClientRect().width;
    const containerLeft = document.getElementById('Container').getBoundingClientRect().left;
    cactus1move();
}
const cactus1move = setInterval(() => {
    if (cactusTop <= dinoBottom && dinoRight >= cactusLeft && cactusRight >= dinoLeft) {
        ...
    } else if (cactusLeft <= containerLeft + 10 && cactusLeft >= containerLeft){
        ...
    } else {
        ...
    }
}, 20)

javascript function

Answer 1

Answer №1

function initialize() {
    const dinoRight = document.getElementById('dino').getBoundingClientRect().left + document.getElementById('dino').getBoundingClientRect().width;
    const dinoLeft = document.getElementById('dino').getBoundingClientRect().left; 
    const dinoHeight = document.getElementById('dino').getBoundingClientRect().height;
    const cactusTop = document.getElementById('cactus').getBoundingClientRect().top;
    const cactusWidth = document.getElementById('cactus').getBoundingClientRect().width;
    const containerLeft = document.getElementById('Container').getBoundingClientRect().left;
    moveCactus1(dinoRight, dinoLeft);
}


//not sure if you can pass it directly to the interval
const moveCactus1 = setInterval((dino_right, dino_left) => {
    if (cactusTop <= dinoBottom && dinoRight >= cactusLeft && cactusRight >= dinoLeft) {
        // Actions to take if conditions are met
    } else if (cactusLeft <= containerLeft+10 && cactusLeft >= containerLeft){
        // Actions to take if conditions are met
    } else {
        // Actions to take if conditions are not met
    }
}, 20);


//if it does not work you can pass the parameters to a function and then down to the interval
const moveCactus2 = (dino_right, dino_left) => {
    setInterval((dino_right, dino_left) => {
        if (cactusTop <= dinoBottom && dinoRight >= cactusLeft && cactusRight >= dinoLeft) {
            // Actions to take if conditions are met
        } else if (cactusLeft <= containerLeft+10 && cactusLeft >= containerLeft){
            // Actions to take if conditions are met
        } else {
            // Actions to take if conditions are not met
        }
    }, 20);
}

Answer 2

function initialize() {
    const dinoRight = document.getElementById('dino').getBoundingClientRect().left + document.getElementById('dino').getBoundingClientRect().width;
    const dinoLeft = document.getElementById('dino').getBoundingClientRect().left; 
    const dinoHeight = document.getElementById('dino').getBoundingClientRect().height;
    const cactusTop = document.getElementById('cactus').getBoundingClientRect().top;
    const cactusWidth = document.getElementById('cactus').getBoundingClientRect().width;
    const containerLeft = document.getElementById('Container').getBoundingClientRect().left;
    moveCactus1(dinoRight, dinoLeft);
}


//not sure if you can pass it directly to the interval
const moveCactus1 = setInterval((dino_right, dino_left) => {
    if (cactusTop <= dinoBottom && dinoRight >= cactusLeft && cactusRight >= dinoLeft) {
        // Actions to take if conditions are met
    } else if (cactusLeft <= containerLeft+10 && cactusLeft >= containerLeft){
        // Actions to take if conditions are met
    } else {
        // Actions to take if conditions are not met
    }
}, 20);


//if it does not work you can pass the parameters to a function and then down to the interval
const moveCactus2 = (dino_right, dino_left) => {
    setInterval((dino_right, dino_left) => {
        if (cactusTop <= dinoBottom && dinoRight >= cactusLeft && cactusRight >= dinoLeft) {
            // Actions to take if conditions are met
        } else if (cactusLeft <= containerLeft+10 && cactusLeft >= containerLeft){
            // Actions to take if conditions are met
        } else {
            // Actions to take if conditions are not met
        }
    }, 20);
}

Answer 3

Answer №2

When writing your code, make sure to consider the scope of variables by declaring them appropriately. Variables declared inside functions are only accessible within that function, limiting their usefulness. To ensure both functions can access the variables, declare them outside the functions as shown below:

let dinoRight, dinoLeft, dinoHeight, cactusTop, cactusWidth, containerLeft;
const spawn = () => {
    dinoRight = document.getElementById('dino').getBoundingClientRect().left + document.getElementById('dino').getBoundingClientRect().width;
    dinoLeft = document.getElementById('dino').getBoundingClientRect().left; 
    dinoHeight = document.getElementById('dino').getBoundingClientRect().height;
    cactusTop = document.getElementById('cactus').getBoundingClientRect().top;
    cactusWidth = document.getElementById('cactus').getBoundingClientRect().width;
    containerLeft = document.getElementById('Container').getBoundingClientRect().left;
    cactus1move();
}
const cactus1move = setInterval(() => {
    if (cactusTop <= dinoBottom && dinoRight >= cactusLeft && cactusRight >= dinoLeft) {
        ...
    } else if (cactusLeft <= containerLeft + 10 && cactusLeft >= containerLeft){
        ...
    } else {
        ...
    }
}, 20)

Answer 4

When writing your code, make sure to consider the scope of variables by declaring them appropriately. Variables declared inside functions are only accessible within that function, limiting their usefulness. To ensure both functions can access the variables, declare them outside the functions as shown below:

let dinoRight, dinoLeft, dinoHeight, cactusTop, cactusWidth, containerLeft;
const spawn = () => {
    dinoRight = document.getElementById('dino').getBoundingClientRect().left + document.getElementById('dino').getBoundingClientRect().width;
    dinoLeft = document.getElementById('dino').getBoundingClientRect().left; 
    dinoHeight = document.getElementById('dino').getBoundingClientRect().height;
    cactusTop = document.getElementById('cactus').getBoundingClientRect().top;
    cactusWidth = document.getElementById('cactus').getBoundingClientRect().width;
    containerLeft = document.getElementById('Container').getBoundingClientRect().left;
    cactus1move();
}
const cactus1move = setInterval(() => {
    if (cactusTop <= dinoBottom && dinoRight >= cactusLeft && cactusRight >= dinoLeft) {
        ...
    } else if (cactusLeft <= containerLeft + 10 && cactusLeft >= containerLeft){
        ...
    } else {
        ...
    }
}, 20)

Answer 5

Answer №3

It's best practice to pass parameters when calling a method instead of relying on global variables. This ensures that the method can be used independently and avoids unnecessary dependencies.

Below, I demonstrate calling the cactus1move method with the necessary values wrapped in an object. Inside the cactus1move function, I use destructuring assignment to extract the values from the object for further processing.

const spawn = () => {
  const dinoRight = document.getElementById('dino').getBoundingClientRect().left + document.getElementById('dino').getBoundingClientRect().width;
  const dinoLeft = document.getElementById('dino').getBoundingClientRect().left;
  const dinoHeight = document.getElementById('dino').getBoundingClientRect().height;
  const cactusTop = document.getElementById('cactus').getBoundingClientRect().top;
  const cactusWidth = document.getElementById('cactus').getBoundingClientRect().width;
  const containerLeft = document.getElementById('Container').getBoundingClientRect().left;
  cactus1move({
    dinoRight,
    dinoLeft,
    dinoHeight,
    cactusTop,
    cactusWidth,
    containerLeft
  });
}

const cactus1move = (data) => {
  return setInterval(() => {
    const {
      dinoRight,
      dinoLeft,
      dinoHeight,
      cactusTop,
      cactusWidth,
      containerLeft
    } = data;
    console.log('dinoRight', dinoRight);
    console.log('dinoLeft', dinoLeft);
    console.log('dinoHeight', dinoHeight);
    console.log('cactusTop', cactusTop);
    console.log('cactusWidth', cactusWidth);
    console.log('containerLeft', containerLeft);
  }, 2000);
}

#dino {
  width: 80px;
  height: 80px;
  background-color: #FFBB73;
  float: left;
}

#cactus {
  width: 90px;
  height: 90px;
  background-color: #FFBB33;
  float: left;
}

#Container {
  width: 100px;
  height: 100px;
  background-color: #FFBB13;
  float: left;
}

<div id='dino'></div>
<div id='cactus'></div>
<div id='Container'></div>
<button onclick="spawn()">spawn</button>

Answer 6

It's best practice to pass parameters when calling a method instead of relying on global variables. This ensures that the method can be used independently and avoids unnecessary dependencies.

Below, I demonstrate calling the cactus1move method with the necessary values wrapped in an object. Inside the cactus1move function, I use destructuring assignment to extract the values from the object for further processing.

const spawn = () => {
  const dinoRight = document.getElementById('dino').getBoundingClientRect().left + document.getElementById('dino').getBoundingClientRect().width;
  const dinoLeft = document.getElementById('dino').getBoundingClientRect().left;
  const dinoHeight = document.getElementById('dino').getBoundingClientRect().height;
  const cactusTop = document.getElementById('cactus').getBoundingClientRect().top;
  const cactusWidth = document.getElementById('cactus').getBoundingClientRect().width;
  const containerLeft = document.getElementById('Container').getBoundingClientRect().left;
  cactus1move({
    dinoRight,
    dinoLeft,
    dinoHeight,
    cactusTop,
    cactusWidth,
    containerLeft
  });
}

const cactus1move = (data) => {
  return setInterval(() => {
    const {
      dinoRight,
      dinoLeft,
      dinoHeight,
      cactusTop,
      cactusWidth,
      containerLeft
    } = data;
    console.log('dinoRight', dinoRight);
    console.log('dinoLeft', dinoLeft);
    console.log('dinoHeight', dinoHeight);
    console.log('cactusTop', cactusTop);
    console.log('cactusWidth', cactusWidth);
    console.log('containerLeft', containerLeft);
  }, 2000);
}

#dino {
  width: 80px;
  height: 80px;
  background-color: #FFBB73;
  float: left;
}

#cactus {
  width: 90px;
  height: 90px;
  background-color: #FFBB33;
  float: left;
}

#Container {
  width: 100px;
  height: 100px;
  background-color: #FFBB13;
  float: left;
}

<div id='dino'></div>
<div id='cactus'></div>
<div id='Container'></div>
<button onclick="spawn()">spawn</button>

How to retrieve the value of a variable from one JavaScript function and pass it to another

Answer №1

Answer №2

Answer №3

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