Stock - multi-stage transaction process with confirmation

[elainechan]

1. submit Buy or Sell intention
2. Edit:
   • hide Buy button, hide Sell button
   • show input for entering number of shares
   • set state quantity to input value
   • show Review button
   • validate input value (must be number, total value <= Account.Cash)
   • submit for Review
3. Review
   • show Edit button, show Confirm button
   • if Edit: go to Review; else if Confirm: handleConfirm()

Functions:

handleBuyIntention() {}
handleSellIntention() {}
handleEdit() {}
handleReview() {}
handleConfirm() {}

Bindings:

this.handleBuyIntention = this.handleBuyIntention.bind(this);
this.handleSellIntention = this.handleSellIntention.bind(this);
this.handleReview = this.handleReview.bind(this);
this.handleEdit = this.handleEdit.bind(this);
this.handleConfirm = this.handleConfirm.bind(this);