Expand subcomponent rows by default with react-table

In order to expand all rows from the beginning, you can use the props defaultExpanded in which you give all the rows index you want to expand. (In this case, all of them), like this :

  render() {
    // Set all the rows index to true
    const defaultExpandedRows = data.map((element, index) => {return {index: true}});
    return (
      <div>
        <ReactTable
          data={data}
          // Use it here
          defaultExpanded={defaultExpandedRows}
          columns={columns}
          defaultPageSize={10}
          className="-striped -highlight"
          SubComponent={subComponent}
        />
      </div>
    );
  }

For more information, you can look here.