How can I loop a component like ObjectRow in React JSX?

General Discussions
,
#1

I’m attempting to achieve the following in React JSX (react for loop), where ObjectRow is a separate component:

<tbody>
    for (var i=0; i < numrows; i++) {
        <ObjectRow/>
    } 
</tbody>

I understand that this isn’t valid JSX because JSX compiles to function calls. However, coming from templates and being new to JSX, I’m uncertain how to accomplish this task of adding a component multiple times.

#2

Hello Miroslav,

You can achieve this using the map method of arrays in ES6 syntax within JSX:

<tbody> {items.map(item => <ObjectRow key={item.id} name={item.name} />)} </tbody>

Make sure to include the key property to help React identify each element uniquely when rendering arrays of components like ObjectRow.

#3

Hey Miroslavrelevic,

here is the answer to the question,

You can achieve this using the map method of arrays in ES6 syntax within JSX:

` {items.map(item => )}`

Make sure to include the key property to help React identify each element uniquely when rendering arrays of components like ObjectRow.

#4

Dear MiroslavRalevic

There are multiple ways to achieve rendering multiple instances of the ObjectRow component in JSX. Since JSX compiles down to JavaScript, any valid JavaScript approach will work effectively.

If you have a number of rows (numrows) rather than an array of objects:

Using Array.prototype.map within the return block:

render() {
  return (
    <tbody>
      {Array(numrows).fill(null).map((value, index) => (
        <ObjectRow key={index} />
      ))}
    </tbody>
  );
}

Using a normal JavaScript for loop outside the return block:

render() {
  let rows = [];
  for (let i = 0; i < numrows; i++) {
    rows.push(<ObjectRow key={i} />);
  }
  return (
    <tbody>{rows}</tbody>
  );
}

Using an immediately invoked function expression (IIFE) within the return block:

render() {
  return (
    <tbody>
      {(() => {
        let rows = [];
        for (let i = 0; i < numrows; i++) {
          rows.push(<ObjectRow key={i} />);
        }
        return rows;
      })()}
    </tbody>
  );
}

If you have an array of objects (objectRows):

Using Array.prototype.map within the return block to map each object to an ObjectRow component:

render() {
  return (
    <tbody>
      {objectRows.map((row, index) => (
        <ObjectRow key={index} data={row} />
      ))}
    </tbody>
  );
}

Using a normal JavaScript for loop outside the return block to iterate over objectRows:

render() {
  let rows = [];
  for (let i = 0; i < objectRows.length; i++) {
    rows.push(<ObjectRow key={i} data={objectRows[i]} />);
  }
  return (
    <tbody>{rows}</tbody>
  );
}

Using an immediately invoked function expression (IIFE) within the return block to iterate over objectRows:

render() {
  return (
    <tbody>
      {(() => {
        const rows = [];
        for (let i = 0; i < objectRows.length; i++) {
          rows.push(<ObjectRow key={i} data={objectRows[i]} />);
        }
        return rows;
      })()}
    </tbody>
  );
}

These examples demonstrate different ways to dynamically generate and render multiple ObjectRow components in JSX, catering to both scenarios of having a fixed number of rows or an array of objects. Each approach uses JavaScript’s capabilities effectively within the JSX environment to achieve the desired rendering.