create fn for chenge CSS style in js

I need to create a function for changing the CSS Style like the below:
(because I use this several times in my code)

document.querySelector('.number').style.width = '30rem';
document.querySelector('.number').style.color = 'green';
document.querySelector('body').style.backgroundColor = 'green';

can use like displayStyleNumber function:

const displayStyleNumber = (classElement, property, value) => {
  const displayCssStyle = `document.querySelector('${classElement}').style.${property} = '${value}';`
  return displayCssStyle;
}

when I use it, doesn’t work!!!
which part is wrong?

>Solution :

Did you mean?:

const displayStyleNumber = (classElement, property, value) => {
  document.querySelector(classElement).style[property] = value;
}

<button id="btn" onclick="displayStyleNumber('#btn', 'backgroundColor', 'red')">click me</button>

In your current form, the code creates a string and then returns it, it won’t execute it

Also, name of this function is misleading