javascript source code of ContributeForm

import React,{ Component } from 'react';
import { Form, Button, Input, Message} from 'semantic-ui-react';
import Campaign from '../ethereum/campaign';
import web3 from '../ethereum/web3';
import {Router} from '../routes' 

class ContributeForm extends Component{
    state = {
        value : '',
        errorMessage : '',
        loading : false
    };

    onSubmit = async event => {
        event.preventDefault();

        this.setState({ loading : true , errorMessage : ''});

        const campaign = Campaign(this.props.address);
        try{
            const accounts = await web3.eth.getAccounts();
            await campaign.methods.contribute().send({
                from : accounts[0],
                value : web3.utils.toWei(this.state.value,'ether')
            });

            Router.replaceRoute(`/campaigns/${this.props.address}`)
        }
        catch(err){
            this.setState({ errorMessage : err.message });
        }
        this.setState({ loading : false });
    }

    render(){
        return(
            <Form onSubmit={this.onSubmit} error={!!this.state.errorMessage}>
                <Form.Field>
                    <label>Amount to Contribute</label>
                    <Input 
                        label="ether" 
                        labelPosition="right" 
                        value={this.state.value}
                        onChange = {event => this.setState ( { value : event.target.value })}
                    />
                </Form.Field>
                
                <Message error header="Oops!" content={this.state.errorMessage} />

                <Button loading={this.state.loading} primary>Contribute!</Button>
            </Form>
        );
    }
}

export default ContributeForm;