Make add token screen a fully working form

Entering the address of a valid HumanStandardToken even auto-fills the other fields!

ui/app/add-token.js

@@ -4,21 +4,37 @@ const h = require('react-hyperscript')
 const connect = require('react-redux').connect
 const actions = require('./actions')
 
+const ethUtil = require('ethereumjs-util')
+const abi = require('human-standard-token-abi')
+const Eth = require('ethjs-query')
+const EthContract = require('ethjs-contract')
+
+const emptyAddr = '0x0000000000000000000000000000000000000000'
+
 module.exports = connect(mapStateToProps)(AddTokenScreen)
 
 function mapStateToProps (state) {
-  return {}
+  return {
+  }
 }
 
 inherits(AddTokenScreen, Component)
 function AddTokenScreen () {
-  this.state = { warning: null }
+  this.state = {
+    warning: null,
+    address: null,
+    symbol: 'TOKEN',
+    decimals: 18,
+  }
   Component.call(this)
 }
 
 AddTokenScreen.prototype.render = function () {
+  const props = this.props
+
   const state = this.state
-  const { warning } = state
+  const { warning, address, symbol, decimals } = state
+
   return (
     h('.flex-column.flex-grow', [
 
@@ -48,6 +64,26 @@ AddTokenScreen.prototype.render = function () {
           },
         }, [
 
+          h('div', [
+            h('span', {
+              style: { fontWeight: 'bold', paddingRight: '10px'},
+            }, 'Token Address'),
+          ]),
+
+          h('section.flex-row.flex-center', [
+            h('input#token-address', {
+              name: 'address',
+              placeholder: 'Token Address',
+              onChange: this.tokenAddressDidChange.bind(this),
+              style: {
+                width: 'inherit',
+                flex: '1 0 auto',
+                height: '30px',
+                margin: '8px',
+              },
+            }),
+          ]),
+
           h('div', [
             h('span', {
               style: { fontWeight: 'bold', paddingRight: '10px'},
@@ -57,17 +93,43 @@ AddTokenScreen.prototype.render = function () {
           h('div', { style: {display: 'flex'} }, [
             h('input#token_symbol', {
               placeholder: `Like "ETH"`,
+              value: symbol,
               style: {
                 width: 'inherit',
                 flex: '1 0 auto',
                 height: '30px',
                 margin: '8px',
               },
-              onKeyPress (event) {
-                if (event.key === 'Enter') {
-                  var element = event.target
-                  var newRpc = element.value
-                }
+              onChange: (event) => {
+                var element = event.target
+                var symbol = element.value
+                this.setState({ symbol })
+              },
+            }),
+          ]),
+
+          h('div', [
+            h('span', {
+              style: { fontWeight: 'bold', paddingRight: '10px'},
+            }, 'Decimals of Precision'),
+          ]),
+
+          h('div', { style: {display: 'flex'} }, [
+            h('input#token_decimals', {
+              value: decimals,
+              type: 'number',
+              min: 0,
+              max: 36,
+              style: {
+                width: 'inherit',
+                flex: '1 0 auto',
+                height: '30px',
+                margin: '8px',
+              },
+              onChange: (event) => {
+                var element = event.target
+                var decimals = element.value.trim()
+                this.setState({ decimals })
               },
             }),
           ]),
@@ -77,9 +139,11 @@ AddTokenScreen.prototype.render = function () {
               alignSelf: 'center',
             },
             onClick (event) {
-              event.preventDefault()
-              var tokenSymbolEl = document.querySelector('input#token_symbol')
-              var tokenSymbol = tokenSymbolEl.value
+              const valid = this.validateInputs()
+              if (!valid) return
+
+              const { address, symbol, decimals } = state
+              this.props.dispatch(addToken(address.trim(), symbol.trim(), decimals))
             },
           }, 'Add'),
         ]),
@@ -88,3 +152,69 @@ AddTokenScreen.prototype.render = function () {
   )
 }
 
+AddTokenScreen.prototype.componentWillMount = function () {
+  if (typeof global.ethereumProvider === 'undefined') return
+
+  this.eth = new Eth(global.ethereumProvider)
+  this.contract = new EthContract(this.eth)
+  this.TokenContract = this.contract(abi)
+}
+
+AddTokenScreen.prototype.tokenAddressDidChange = function (event) {
+  const el = event.target
+  const address = el.value.trim()
+  if (ethUtil.isValidAddress(address) && address !== emptyAddr) {
+    this.setState({ address })
+    this.attemptToAutoFillTokenParams(address)
+  }
+}
+
+AddTokenScreen.prototype.validateInputs = function () {
+  let msg = ''
+  const state = this.state
+  const { address, symbol, decimals } = state
+
+  const validAddress = ethUtil.isValidAddress(address)
+  if (!validAddress) {
+    msg += 'Address is invalid. '
+  }
+
+  const validDecimals = decimals >= 0 && decimals < 36
+  if (!validDecimals) {
+    msg += 'Decimals must be at least 0, and not over 36. '
+  }
+
+  const symbolLen = symbol.trim().length
+  const validSymbol = symbolLen > 0 && symbolLen < 10
+  if (!validSymbol) {
+    msg += 'Symbol must be between 0 and 10 characters.'
+  }
+
+  const isValid = validAddress && validDecimals
+
+  if (!isValid) {
+    this.setState({
+      warning: msg,
+    })
+  } else {
+    this.setState({ warning: null })
+  }
+
+  return isValid
+}
+
+AddTokenScreen.prototype.attemptToAutoFillTokenParams = async function (address) {
+  const contract = this.TokenContract.at(address)
+
+  const results = await Promise.all([
+    contract.symbol(),
+    contract.decimals(),
+  ])
+
+  const [ symbol, decimals ] = results
+  if (symbol && decimals) {
+    console.log('SETTING SYMBOL AND DECIMALS', { symbol, decimals })
+    this.setState({ symbol: symbol[0], decimals: decimals[0].toString() })
+  }
+}
+