react_demo/calc/src/components/calculator/operatorButton.jsx

import React, { Component } from 'react';
import {connect} from 'react-redux';
import ACTIONS from '../../redux/action';

class OperatorButton extends Component {
    state = {  } 
    render() { 
        return (<button onClick={() => this.props.choose_operation(this.props.operator)}>{this.props.operator}</button>);
    }
}
 
const mapDispatchToProps = {
    choose_operation: operator => {
        return  {
            type: ACTIONS.CHOOSE_OPERATION,
            operator: operator,
        }
    }
};

export default connect(null,mapDispatchToProps)(OperatorButton);