Improve ux for low gas price set (#5862)

* Show user warning if they set gas price below safelow minimum, error if 0.

* Properly cache basic price estimate data.

* Default retry price to recommended price if original price was 0x0

* Use mock fetch in send-new-ui integration tests.

1 files changed, 36 insertions, 0 deletions

diff --git a/ui/app/selectors/custom-gas.js b/ui/app/selectors/custom-gas.js
index 59f240f9c..91c9109a5 100644
--- a/ui/app/selectors/custom-gas.js
+++ b/ui/app/selectors/custom-gas.js
@@ -2,6 +2,7 @@ import { pipe, partialRight } from 'ramda'
 import {
   conversionUtil,
   multiplyCurrencies,
+  conversionGreaterThan,
 } from '../conversion-util'
 import {
   getCurrentCurrency,
@@ -38,6 +39,8 @@ const selectors = {
   getRenderableBasicEstimateData,
   getRenderableEstimateDataForSmallButtonsFromGWEI,
   priceEstimateToWei,
+  getSafeLowEstimate,
+  isCustomPriceSafe,
 }
 
 module.exports = selectors
@@ -96,6 +99,39 @@ function getDefaultActiveButtonIndex (gasButtonInfo, customGasPriceInHex, gasPri
   })
 }
 
+function getSafeLowEstimate (state) {
+  const {
+    gas: {
+      basicEstimates: {
+        safeLow,
+      },
+    },
+  } = state
+
+  return safeLow
+}
+
+function isCustomPriceSafe (state) {
+  const safeLow = getSafeLowEstimate(state)
+  const customGasPrice = getCustomGasPrice(state)
+
+  if (!customGasPrice) {
+    return true
+  }
+
+  const customPriceSafe = conversionGreaterThan(
+    {
+      value: customGasPrice,
+      fromNumericBase: 'hex',
+      fromDenomination: 'WEI',
+      toDenomination: 'GWEI',
+    },
+    { value: safeLow, fromNumericBase: 'dec' }
+  )
+
+  return customPriceSafe
+}
+
 function getBasicGasEstimateBlockTime (state) {
   return state.gas.basicEstimates.blockTime
 }