1 files changed, 93 insertions, 0 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),
+  })
+}