React - Create nested components with loops

Question

I have a little issue with React. I can't create a nested component with a for loop. What I want to do is create 9 cells of a table and then create 3 rows with 3 cells for every row and after that mount the 3 rows together and create a board 9x9.

Let say that I want to get something like this, but using a loop

class Board extends React.Component {     
renderSquare(i) {
    return <Square value={this.props.squares[i]} onClick={() => this.props.onClick(i)} />;
}

render(){    
    return(
        <div>
            <div className="board-row">
                {this.renderSquare(0)}
                {this.renderSquare(1)}
                {this.renderSquare(2)}
            </div>
            <div className="board-row">
                {this.renderSquare(3)}
                {this.renderSquare(4)}
                {this.renderSquare(5)}
            </div>
            <div className="board-row">
                {this.renderSquare(6)}
                {this.renderSquare(7)}
                {this.renderSquare(8)}
            </div>
        </div>
    );        
}

}

I searched others question for hours and I think my code is almost correct but it does not render what I want. I only get a white page.

here is my code:

class Board extends React.Component { 

renderSquare(i) {
    return <Square value={this.props.squares[i]} onClick={() => this.props.onClick(i)} />;
}

createCells(i){
    if(i%3){return;}
    var index = this.fillN(Array(i)); //index=[0,1,2,3,4,5,6,7,8]
    var cells = [];
    index.forEach(function(i){
        cells.push(() => {
            return(
                <div>
                    {this.renderSquare(i)}
                </div>
            );
        });
    });
    return cells;
}

createRows(cells){
    var index = this.fillMod3(Array(3)); //index=[0,3,6]
    var rows = []
    index.forEach(function(i){
        rows.push(() => {
            return(
                <div>
                    {cells[i]}
                    {cells[i+1]}
                    {cells[i+2]}
                </div>
            );
        });
    });
    return rows;
}

render(){    
    var cells = this.createCells(9);
    var rows = this.createRows(cells);
    var board = [];
    var index = this.fillN(Array(1));

    index.forEach(function(row){
        board.push(() => {
            return(
                <div>{row}</div>
            );
        });
    })

    return(
        <div>
            {board[0]}
        </div>
    );        
}

I always get on the screen something like this:

<Board>
  <div> /*empty*/ </div>
</Board>

I want to clarify that I am sure that the rest of the code with which that component (Board) interacts has no issues.

I am new in react and if someoane can help me i will apreciate very much. Sorry for my poor English

EDIT1: following marklew examples i should be able to do something like this

    render(){   
    var index1 = this.fillN(Array(3)); //index1=[0,1,2]
    var index2 = this.fillN(Array(3)); //index2=[0,1,2]

    return(
        <div>
            {index1.map((e1,i1) => {
                return(
                    <div key={i1} className="board-row">
                        {index2.map((e2, i2) => {
                            return(
                                <p key={i2+10}>
                                    {this.renderSquare(i2)}
                                </p>
                            )
                        })}
                    </div>
                )    
            })}
        </div>
    );

}

but it doesn't do what I want. I obtain just a column with 9 cells and the cells are the same objects. I dont understand why. (I understand that are the same objects because i assign a handle function onClick when I create them like that:

<Board 
     onClick={(i) => this.handleClick(i)} //handleClick just draws a X in the cell
     />

and I get the X drown in 3 cells simultaneously

EDIT2: I reached a solution:

render(){   
    var index1 = this.fillMod3(Array(3));        

    return(
        <div>
            {index1.map((e,i) => {
                return(
                    <div key={i} className="board-row">
                        {this.renderSquare(e)}
                        {this.renderSquare(e+1)}
                        {this.renderSquare(e+2)}
                    </div>
                )    
            })}
        </div>
    );

}

}

but is not what I want. I want another loop even for the intern renderSquare(i) function.

Answer 1

To render a list of elements inside JSX, you can do something like that:

render() {
    return <div>
        {
            [1,2,3].map ( (n) => {
                return this.renderSquare(n)
            })

        }
    </div>;
}   

Just wrap your array of components into {} in your JSX.

To clarify a bit, this is the same logic of:

return <div>
    {
        [
            <h1 key="1">Hello 1</h1>,
            <h1 key="2">Hello 2</h1>,
            <h1 key="3">Hello 3</h1>
        ]           
    }
</div>;

Note that everytime you render an array of components, you must provide a key prop, as pointed here.

Also, if you want simply print row value in your render function, you should replace:

index.forEach(function(row){
    board.push(() => {
        return(
            <div>{row}</div>
        );
    });
})

with:

index.forEach( (row, index) => {
    board.push(<div key={index}>{row}</div>)
})

or, yet, replacing forEach and push with map:

board = index.map( (row, index) => <div key={index}>{row}</div> )

EDIT I created a fiddle with a 9x9 board using your code as a base: https://jsfiddle.net/mrlew/cLbyyL27/ (you can click on the cell to select it)