embark/templates/demo/app/components/blockchain.js

import EmbarkJS from 'Embark/EmbarkJS';
import SimpleStorage from 'Embark/contracts/SimpleStorage';
import React from 'react';
import { Form, FormGroup, FormControl, HelpBlock, Button } from 'react-bootstrap';
 
class Blockchain extends React.Component {

    constructor(props) {
      super(props);
  
      this.state = {
        valueSet: 10,
        valueGet: "",
        logs: []
      }
    }
  
    handleChange(e){
      this.setState({valueSet: e.target.value});
    }
  
    setValue(e){
      e.preventDefault();
  
      var value = parseInt(this.state.valueSet, 10);
  
      // If web3.js 1.0 is being used
      if (EmbarkJS.isNewWeb3()) {
        SimpleStorage.methods.set(value).send({from: web3.eth.defaultAccount});
        this._addToLog("SimpleStorage.methods.set(value).send({from: web3.eth.defaultAccount})");
      } else {
        SimpleStorage.set(value);
        this._addToLog("#blockchain", "SimpleStorage.set(" + value + ")");
      }
    }
  
    getValue(e){
      e.preventDefault();
      
      if (EmbarkJS.isNewWeb3()) {
        SimpleStorage.methods.get().call()
          .then(_value => this.setState({valueGet: _value}))
        this._addToLog("SimpleStorage.methods.get(console.log)");
      } else {
        SimpleStorage.get()
          .then(_value => this.setState({valueGet: _value}));
        this._addToLog("SimpleStorage.get()");
      }
    }
  
    _addToLog(txt){
      this.state.logs.push(txt);
      this.setState({logs: this.state.logs});
    }
  
    render(){
      return (<React.Fragment>
          <h3> 1. Set the value in the blockchain</h3>
          <Form inline>
            <FormGroup>
              <FormControl
                type="text"
                defaultValue={this.state.valueSet}
                onChange={(e) => this.handleChange(e)} />
              {' '}
              <Button bsStyle="primary" onClick={(e) => this.setValue(e)}>Set Value</Button>
              <HelpBlock>Once you set the value, the transaction will need to be mined and then the value will be updated on the blockchain.</HelpBlock>
            </FormGroup>
          </Form>
          
          <h3> 2. Get the current value</h3>
          <Form inline>
            <FormGroup>
              <HelpBlock>current value is <span className="value">{this.state.valueGet}</span></HelpBlock>
              <Button bsStyle="primary" onClick={(e) => this.getValue(e)}>Get Value</Button>
              <HelpBlock>Click the button to get the current value. The initial value is 100.</HelpBlock>
            </FormGroup>
          </Form>
          
          <h3> 3. Contract Calls </h3>
          <p>Javascript calls being made: </p>
          <div className="logs">
          {
            this.state.logs.map((item, i) => <p key={i}>{item}</p>)
          }
          </div>
      </React.Fragment>
      );
    }
  }

  export default Blockchain;