Add currency-input component to correct send amount behaviour and move currency display value state to parent component.

2 files changed, 101 insertions, 28 deletions

diff --git a/ui/app/components/currency-input.js b/ui/app/components/currency-input.js
new file mode 100644
index 000000000..5e534d87b
--- /dev/null
+++ b/ui/app/components/currency-input.js
@@ -0,0 +1,93 @@
+const Component = require('react').Component
+const h = require('react-hyperscript')
+const inherits = require('util').inherits
+
+module.exports = CurrencyInput
+
+inherits(CurrencyInput, Component)
+function CurrencyInput (props) {
+  Component.call(this)
+
+  this.state = {
+    value: sanitizeValue(props.value),
+  }
+}
+
+function removeNonDigits (str) {
+  return str.match(/\d|$/g).join('')
+}
+
+// Removes characters that are not digits, then removes leading zeros
+function sanitizeInteger (val) {
+  return String(parseInt(removeNonDigits(val) || '0', 10))
+}
+
+function sanitizeDecimal (val) {
+  return removeNonDigits(val)
+}
+
+// Take a single string param and returns a non-negative integer or float as a string.
+// Breaks the input into three parts: the integer, the decimal point, and the decimal/fractional part.
+// Removes leading zeros from the integer, and non-digits from the integer and decimal
+// The integer is returned as '0' in cases where it would be empty. A decimal point is
+// included in the returned string if one is included in the param
+// Examples:
+//  sanitizeValue('0') -> '0'
+//  sanitizeValue('a') -> '0'
+//  sanitizeValue('010.') -> '10.'
+//  sanitizeValue('0.005') -> '0.005'
+//  sanitizeValue('22.200') -> '22.200'
+//  sanitizeValue('.200') -> '0.200'
+//  sanitizeValue('a.b.1.c,89.123') -> '0.189123'
+function sanitizeValue (value) {
+  let [,integer, point, decimal] = (/([^.]*)([.]?)([^.]*)/).exec(value)
+
+  integer = sanitizeInteger(integer) || '0'
+  decimal = sanitizeDecimal(decimal)
+
+  return `${integer}${point}${decimal}`
+}
+
+CurrencyInput.prototype.handleChange = function (newValue) {
+  const { onInputChange } = this.props
+
+  this.setState({ value: sanitizeValue(newValue) })
+
+  onInputChange(sanitizeValue(newValue))
+}
+
+// If state.value === props.value plus a decimal point, or at least one
+// zero or a decimal point and at least one zero, then this returns state.value
+// after it is sanitized with getValueParts
+CurrencyInput.prototype.getValueToRender = function () {
+  const { value } = this.props
+  const { value: stateValue } = this.state
+
+  const trailingStateString = (new RegExp(`^${value}(.+)`)).exec(stateValue)
+  const trailingDecimalAndZeroes = trailingStateString && (/^[.0]0*/).test(trailingStateString[1])
+
+  return sanitizeValue(trailingDecimalAndZeroes
+    ? stateValue
+    : value)
+}
+
+CurrencyInput.prototype.render = function () {
+  const {
+    className,
+    placeholder,
+    readOnly,
+  } = this.props
+
+  const inputSizeMultiplier = readOnly ? 1 : 1.2
+
+  const valueToRender = this.getValueToRender()
+
+  return h('input', {
+    className,
+    value: valueToRender,
+    placeholder,
+    size: valueToRender.length * inputSizeMultiplier,
+    readOnly,
+    onChange: e => this.handleChange(e.target.value),
+  })
+}
diff --git a/ui/app/components/send/currency-display.js b/ui/app/components/send/currency-display.js
index 45986e371..8b72b3e6d 100644
--- a/ui/app/components/send/currency-display.js
+++ b/ui/app/components/send/currency-display.js
@@ -1,6 +1,7 @@
 const Component = require('react').Component
 const h = require('react-hyperscript')
 const inherits = require('util').inherits
+const CurrencyInput = require('../currency-input')
 const { conversionUtil, multiplyCurrencies } = require('../../conversion-util')
 
 module.exports = CurrencyDisplay
@@ -8,10 +9,6 @@ module.exports = CurrencyDisplay
 inherits(CurrencyDisplay, Component)
 function CurrencyDisplay () {
   Component.call(this)
-
-  this.state = {
-    value: null,
-  }
 }
 
 function isValidInput (text) {
@@ -49,13 +46,11 @@ CurrencyDisplay.prototype.render = function () {
     convertedCurrency,
     readOnly = false,
     inError = false,
-    value: initValue,
+    value,
     handleChange,
-    validate,
   } = this.props
-  const { value } = this.state
 
-  const initValueToRender = conversionUtil(initValue, {
+  const valueToRender = conversionUtil(value, {
     fromNumericBase: 'hex',
     toNumericBase: 'dec',
     fromDenomination: 'WEI',
@@ -63,7 +58,7 @@ CurrencyDisplay.prototype.render = function () {
     conversionRate,
   })
 
-  const convertedValue = conversionUtil(value || initValueToRender, {
+  const convertedValue = conversionUtil(valueToRender, {
     fromNumericBase: 'dec',
     fromCurrency: primaryCurrency,
     toCurrency: convertedCurrency,
@@ -84,29 +79,14 @@ CurrencyDisplay.prototype.render = function () {
 
       h('div.currency-display__input-wrapper', [
 
-        h('input', {
+        h(CurrencyInput, {
           className: primaryBalanceClassName,
-          value: `${value || initValueToRender}`,
+          value: `${valueToRender}`,
           placeholder: '0',
-          size: (value || initValueToRender).length * inputSizeMultiplier,
           readOnly,
-          onChange: (event) => {
-            let newValue = event.target.value
-
-            if (newValue === '') {
-              newValue = '0'
-            } else if (newValue.match(/^0[1-9]$/)) {
-              newValue = newValue.match(/[1-9]/)[0]
-            }
-
-            if (newValue && !isValidInput(newValue)) {
-              event.preventDefault()
-            } else {
-              validate(this.getAmount(newValue))
-              this.setState({ value: newValue })
-            }
+          onInputChange: newValue => {
+            handleChange(this.getAmount(newValue))
           },
-          onBlur: event => !readOnly && handleChange(this.getAmount(event.target.value)),
         }),
 
         h('span.currency-display__currency-symbol', primaryCurrency),