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Loop inside React JSX

I'm trying to do something like the following in React JSX (where ObjectRow is a separate component):

    for (var i=0; i < numrows; i++) {

I realize and understand why this isn't valid JSX, since JSX maps to function calls. However, coming from template land and being new to JSX, I am unsure how I would achieve the above (adding a component multiple times).


  • Think of it like you're just calling JavaScript functions. You can't use a for loop where the arguments to a function call would go:

    return tbody(
        for (let i = 0; i < numrows; i++) {

    See how the function tbody is being passed a for loop as an argument – leading to a syntax error.

    But you can make an array, and then pass that in as an argument:

    const rows = [];
    for (let i = 0; i < numrows; i++) {
    return tbody(rows);

    You can basically use the same structure when working with JSX:

    const rows = [];
    for (let i = 0; i < numrows; i++) {
        // note: we are adding a key prop here to allow react to uniquely identify each
        // element in this array. see:
        rows.push(<ObjectRow key={i} />);
    return <tbody>{rows}</tbody>;

    Incidentally, my JavaScript example is almost exactly what that example of JSX transforms into. Play around with Babel REPL to get a feel for how JSX works.