Using react-i18next within a class component

Just like t is available as props in a functional component, you can access it from props in a class component after wrapping TradesTableComponent with translate HOC. All you need to do is destructure it from props in render method like

const { t } = this.props;

Relevant code

render() {
    const { t } = this.props;
    return (
      <div className="trades-table__controls-wrap">
        <div className="trades-table__controls">
          <UncontrolledDropdown>
            <DropdownToggle className="icon icon--right" outline size="sm">
              <p>
                {t('history.controls.show')}
                {this.state.rows}
                {t('history.controls.results')}
                <MenuDownIcon />
              </p>
            </DropdownToggle>
            <DropdownMenu className="dropdown__menu">
              <DropdownItem onClick={() => this.changeRowAmount(10)}>10</DropdownItem>
              <DropdownItem onClick={() => this.changeRowAmount(25)}>25</DropdownItem>
              <DropdownItem onClick={() => this.changeRowAmount(50)}>50</DropdownItem>
              <DropdownItem onClick={() => this.changeRowAmount(100)}>100</DropdownItem>
            </DropdownMenu>
          </UncontrolledDropdown>
        </div>
        <div className="trades-table__controls-right">
          <div className="trades-table__control-search">
            <input placeholder="Search" />
            <div className="trades-table__control-search-icon"><MagnifyIcon /></div>
          </div>
        </div>
      </div>
    );
  }

Currently (ie 2021) the docs suggest the packaged HOC withTranslation():

import React from 'react';
import { withTranslation } from 'react-i18next';

class MyComponent extends Component {
  return <p>{this.props.t('key')}</p>
}

export default withTranslation()(MyComponent);

If you like to use namespaces then export:

export default withTranslation('namespace')(MyComponent);

Ref: official docs.