⚛️ React `createElement` vs `cloneElement` — What’s the Difference?

In React, both createElement and cloneElement are used to create React elements—but they solve very different problems.

Understanding when to use each becomes especially important when:

building reusable components
working with props.children
injecting or modifying props dynamically

Let’s break it down clearly.

🚀 TL;DR

React.createElement(type, props, ...children)
👉 Creates a brand-new React element from scratch.
(JSX like <div /> is compiled into createElement.)
React.cloneElement(element, [props], [...children])
👉 Creates a modified copy of an existing element, merging new props and optionally replacing children.
Commonly used to enhance props.children.

🧠 Conceptual Differences

Feature	`createElement`	`cloneElement`
Purpose	Create a new element	Clone and modify an existing element
Typical usage	Behind JSX (`<div />`)	Enhance or decorate `props.children`
Props handling	You provide props directly	Shallow merge; new props override old
Children	Defined at creation time	Replace children only if provided
Key / Ref	Assigned explicitly	Preserved unless overridden

🔧 Example 1: `createElement` (JSX Equivalent)

// JSX
const elJSX = <div className="box">Hello World</div>;

// Equivalent using createElement
const elCreate = React.createElement(
  "div",
  { className: "box" },
  "Hello World"
);

// Dynamic element type
const Tag = isButton ? "button" : "a";
const dynamic = React.createElement(
  Tag,
  { onClick: handleClick },
  "Click Me"
);

👉 JSX is just syntactic sugar for React.createElement.
That’s why you almost never write createElement manually in real apps.

🔧 Example 2: Using `cloneElement` to Inject Props

A very common use case for cloneElement is enhancing children passed to a wrapper component.

function ItemList({ children }) {
  return React.Children.map(children, child => {
    if (!React.isValidElement(child)) return child;

    return React.cloneElement(child, {
      style: {
        ...(child.props.style || {}),
        marginLeft: 8
      },
      className: `${child.props.className || ""} injected`.trim(),
      onClick: e => {
        console.log("Item clicked!");
        child.props.onClick?.(e);
      }
    });
  });
}

// Usage
<ItemList>
  <button onClick={() => alert("A clicked")}>A</button>
  <button>B</button>
</ItemList>

✅ This lets a parent decorate or enhance children
without modifying the child components themselves.

🔧 Example 3: Replacing Children with `cloneElement`

const child = <div>Old</div>;

const newChild = React.cloneElement(child, {}, "New");

// Result: <div>New</div>

📌 Key behavior:

If children are provided, they replace existing ones
If not, original children are preserved

⚠️ Important Notes About `cloneElement`

Props are merged shallowly
Objects like style or className must be merged manually
key and ref are preserved unless explicitly overridden
Overuse can make code harder to reason about

✅ Best Practices

Prefer JSX for everyday development
Use createElement mainly in:
- libraries
- dynamic rendering scenarios without JSX
Use cloneElement when:
- enhancing props.children
- building reusable wrapper components
Always manually merge:
- style
- className
Avoid overusing cloneElement—composition via props is often cleaner

🧾 Final Thoughts

createElement builds elements from scratch and powers JSX
cloneElement enhances existing elements by injecting or modifying props

Think of it this way:

createElement = construction
cloneElement = decoration

Knowing when to use each helps you write cleaner, more flexible, and more maintainable React components—especially in advanced component composition patterns.

React createElement vs cloneElement