Folder restructure (#6304)

* Remove ui/app/keychains/

* Remove ui/app/img/ (unused images)

* Move conversion-util to helpers/utils/

* Move token-util to helpers/utils/

* Move /helpers/*.js inside /helpers/utils/

* Move util tests inside /helpers/utils/

* Renameand move confirm-transaction/util.js to helpers/utils/

* Move higher-order-components to helpers/higher-order-components/

* Move infura-conversion.json to helpers/constants/

* Move all utility functions to helpers/utils/

* Move pages directory to top-level

* Move all constants to helpers/constants/

* Move metametrics inside helpers/

* Move app and root inside pages/

* Move routes inside helpers/

* Re-organize ducks/

* Move reducers to ducks/

* Move selectors inside selectors/

* Move test out of test folder

* Move action, reducer, store inside store/

* Move ui components inside ui/

* Move UI components inside ui/

* Move connected components inside components/app/

* Move i18n-helper inside helpers/

* Fix unit tests

* Fix unit test

* Move pages components

* Rename routes component

* Move reducers to ducks/index

* Fix bad path in unit test

2 files changed, 1117 insertions, 0 deletions

diff --git a/ui/app/ducks/gas/gas-duck.test.js b/ui/app/ducks/gas/gas-duck.test.js
new file mode 100644
index 000000000..4e875e020
--- /dev/null
+++ b/ui/app/ducks/gas/gas-duck.test.js
@@ -0,0 +1,600 @@
+import assert from 'assert'
+import sinon from 'sinon'
+import proxyquire from 'proxyquire'
+
+
+const GasDuck = proxyquire('./gas.duck.js', {
+  '../../../lib/local-storage-helpers': {
+    loadLocalStorageData: sinon.spy(),
+    saveLocalStorageData: sinon.spy(),
+  },
+})
+
+const {
+  basicGasEstimatesLoadingStarted,
+  basicGasEstimatesLoadingFinished,
+  setBasicGasEstimateData,
+  setCustomGasPrice,
+  setCustomGasLimit,
+  setCustomGasTotal,
+  setCustomGasErrors,
+  resetCustomGasState,
+  fetchBasicGasAndTimeEstimates,
+  fetchBasicGasEstimates,
+  gasEstimatesLoadingStarted,
+  gasEstimatesLoadingFinished,
+  setPricesAndTimeEstimates,
+  fetchGasEstimates,
+  setApiEstimatesLastRetrieved,
+} = GasDuck
+const GasReducer = GasDuck.default
+
+describe('Gas Duck', () => {
+  let tempFetch
+  let tempDateNow
+  const mockEthGasApiResponse = {
+    average: 20,
+    avgWait: 'mockAvgWait',
+    block_time: 'mockBlock_time',
+    blockNum: 'mockBlockNum',
+    fast: 30,
+    fastest: 40,
+    fastestWait: 'mockFastestWait',
+    fastWait: 'mockFastWait',
+    safeLow: 10,
+    safeLowWait: 'mockSafeLowWait',
+    speed: 'mockSpeed',
+    standard: 20,
+  }
+  const mockPredictTableResponse = [
+    { expectedTime: 400, expectedWait: 40, gasprice: 0.25, somethingElse: 'foobar' },
+    { expectedTime: 200, expectedWait: 20, gasprice: 0.5, somethingElse: 'foobar' },
+    { expectedTime: 100, expectedWait: 10, gasprice: 1, somethingElse: 'foobar' },
+    { expectedTime: 75, expectedWait: 7.5, gasprice: 1.5, somethingElse: 'foobar' },
+    { expectedTime: 50, expectedWait: 5, gasprice: 2, somethingElse: 'foobar' },
+    { expectedTime: 35, expectedWait: 4.5, gasprice: 3, somethingElse: 'foobar' },
+    { expectedTime: 34, expectedWait: 4.4, gasprice: 3.1, somethingElse: 'foobar' },
+    { expectedTime: 25, expectedWait: 4.2, gasprice: 3.5, somethingElse: 'foobar' },
+    { expectedTime: 20, expectedWait: 4, gasprice: 4, somethingElse: 'foobar' },
+    { expectedTime: 19, expectedWait: 3.9, gasprice: 4.1, somethingElse: 'foobar' },
+    { expectedTime: 15, expectedWait: 3, gasprice: 7, somethingElse: 'foobar' },
+    { expectedTime: 14, expectedWait: 2.9, gasprice: 7.1, somethingElse: 'foobar' },
+    { expectedTime: 12, expectedWait: 2.5, gasprice: 8, somethingElse: 'foobar' },
+    { expectedTime: 10, expectedWait: 2, gasprice: 10, somethingElse: 'foobar' },
+    { expectedTime: 9, expectedWait: 1.9, gasprice: 10.1, somethingElse: 'foobar' },
+    { expectedTime: 5, expectedWait: 1, gasprice: 15, somethingElse: 'foobar' },
+    { expectedTime: 4, expectedWait: 0.9, gasprice: 15.1, somethingElse: 'foobar' },
+    { expectedTime: 2, expectedWait: 0.8, gasprice: 17, somethingElse: 'foobar' },
+    { expectedTime: 1.1, expectedWait: 0.6, gasprice: 19.9, somethingElse: 'foobar' },
+    { expectedTime: 1, expectedWait: 0.5, gasprice: 20, somethingElse: 'foobar' },
+  ]
+  const fetchStub = sinon.stub().callsFake((url) => new Promise(resolve => {
+    const dataToResolve = url.match(/ethgasAPI|gasexpress/)
+      ? mockEthGasApiResponse
+      : mockPredictTableResponse
+    resolve({
+      json: () => new Promise(resolve => resolve(dataToResolve)),
+    })
+  }))
+
+  beforeEach(() => {
+    tempFetch = global.fetch
+    tempDateNow = global.Date.now
+    global.fetch = fetchStub
+    global.Date.now = () => 2000000
+  })
+
+  afterEach(() => {
+    fetchStub.resetHistory()
+    global.fetch = tempFetch
+    global.Date.now = tempDateNow
+  })
+
+  const mockState = {
+    gas: {
+      mockProp: 123,
+    },
+  }
+  const initState = {
+    customData: {
+      price: null,
+      limit: null,
+    },
+    basicEstimates: {
+      average: null,
+      fastestWait: null,
+      fastWait: null,
+      fast: null,
+      safeLowWait: null,
+      blockNum: null,
+      avgWait: null,
+      blockTime: null,
+      speed: null,
+      fastest: null,
+      safeLow: null,
+    },
+    basicEstimateIsLoading: true,
+    errors: {},
+    gasEstimatesLoading: true,
+    priceAndTimeEstimates: [],
+    priceAndTimeEstimatesLastRetrieved: 0,
+    basicPriceAndTimeEstimates: [],
+    basicPriceAndTimeEstimatesLastRetrieved: 0,
+    basicPriceEstimatesLastRetrieved: 0,
+  }
+  const BASIC_GAS_ESTIMATE_LOADING_FINISHED = 'metamask/gas/BASIC_GAS_ESTIMATE_LOADING_FINISHED'
+  const BASIC_GAS_ESTIMATE_LOADING_STARTED = 'metamask/gas/BASIC_GAS_ESTIMATE_LOADING_STARTED'
+  const GAS_ESTIMATE_LOADING_FINISHED = 'metamask/gas/GAS_ESTIMATE_LOADING_FINISHED'
+  const GAS_ESTIMATE_LOADING_STARTED = 'metamask/gas/GAS_ESTIMATE_LOADING_STARTED'
+  const RESET_CUSTOM_GAS_STATE = 'metamask/gas/RESET_CUSTOM_GAS_STATE'
+  const SET_BASIC_GAS_ESTIMATE_DATA = 'metamask/gas/SET_BASIC_GAS_ESTIMATE_DATA'
+  const SET_CUSTOM_GAS_ERRORS = 'metamask/gas/SET_CUSTOM_GAS_ERRORS'
+  const SET_CUSTOM_GAS_LIMIT = 'metamask/gas/SET_CUSTOM_GAS_LIMIT'
+  const SET_CUSTOM_GAS_PRICE = 'metamask/gas/SET_CUSTOM_GAS_PRICE'
+  const SET_CUSTOM_GAS_TOTAL = 'metamask/gas/SET_CUSTOM_GAS_TOTAL'
+  const SET_PRICE_AND_TIME_ESTIMATES = 'metamask/gas/SET_PRICE_AND_TIME_ESTIMATES'
+  const SET_API_ESTIMATES_LAST_RETRIEVED = 'metamask/gas/SET_API_ESTIMATES_LAST_RETRIEVED'
+  const SET_BASIC_API_ESTIMATES_LAST_RETRIEVED = 'metamask/gas/SET_BASIC_API_ESTIMATES_LAST_RETRIEVED'
+  const SET_BASIC_PRICE_ESTIMATES_LAST_RETRIEVED = 'metamask/gas/SET_BASIC_PRICE_ESTIMATES_LAST_RETRIEVED'
+
+  describe('GasReducer()', () => {
+    it('should initialize state', () => {
+      assert.deepEqual(
+        GasReducer({}),
+        initState
+      )
+    })
+
+    it('should return state unchanged if it does not match a dispatched actions type', () => {
+      assert.deepEqual(
+        GasReducer(mockState, {
+          type: 'someOtherAction',
+          value: 'someValue',
+        }),
+        Object.assign({}, mockState.gas)
+      )
+    })
+
+    it('should set basicEstimateIsLoading to true when receiving a BASIC_GAS_ESTIMATE_LOADING_STARTED action', () => {
+      assert.deepEqual(
+        GasReducer(mockState, {
+          type: BASIC_GAS_ESTIMATE_LOADING_STARTED,
+        }),
+        Object.assign({basicEstimateIsLoading: true}, mockState.gas)
+      )
+    })
+
+    it('should set basicEstimateIsLoading to false when receiving a BASIC_GAS_ESTIMATE_LOADING_FINISHED action', () => {
+      assert.deepEqual(
+        GasReducer(mockState, {
+          type: BASIC_GAS_ESTIMATE_LOADING_FINISHED,
+        }),
+        Object.assign({basicEstimateIsLoading: false}, mockState.gas)
+      )
+    })
+
+    it('should set gasEstimatesLoading to true when receiving a GAS_ESTIMATE_LOADING_STARTED action', () => {
+      assert.deepEqual(
+        GasReducer(mockState, {
+          type: GAS_ESTIMATE_LOADING_STARTED,
+        }),
+        Object.assign({gasEstimatesLoading: true}, mockState.gas)
+      )
+    })
+
+    it('should set gasEstimatesLoading to false when receiving a GAS_ESTIMATE_LOADING_FINISHED action', () => {
+      assert.deepEqual(
+        GasReducer(mockState, {
+          type: GAS_ESTIMATE_LOADING_FINISHED,
+        }),
+        Object.assign({gasEstimatesLoading: false}, mockState.gas)
+      )
+    })
+
+    it('should return a new object (and not just modify the existing state object)', () => {
+      assert.deepEqual(GasReducer(mockState), mockState.gas)
+      assert.notEqual(GasReducer(mockState), mockState.gas)
+    })
+
+    it('should set basicEstimates when receiving a SET_BASIC_GAS_ESTIMATE_DATA action', () => {
+      assert.deepEqual(
+        GasReducer(mockState, {
+          type: SET_BASIC_GAS_ESTIMATE_DATA,
+          value: { someProp: 'someData123' },
+        }),
+        Object.assign({basicEstimates: {someProp: 'someData123'} }, mockState.gas)
+      )
+    })
+
+    it('should set priceAndTimeEstimates when receiving a SET_PRICE_AND_TIME_ESTIMATES action', () => {
+      assert.deepEqual(
+        GasReducer(mockState, {
+          type: SET_PRICE_AND_TIME_ESTIMATES,
+          value: { someProp: 'someData123' },
+        }),
+        Object.assign({priceAndTimeEstimates: {someProp: 'someData123'} }, mockState.gas)
+      )
+    })
+
+    it('should set customData.price when receiving a SET_CUSTOM_GAS_PRICE action', () => {
+      assert.deepEqual(
+        GasReducer(mockState, {
+          type: SET_CUSTOM_GAS_PRICE,
+          value: 4321,
+        }),
+        Object.assign({customData: {price: 4321} }, mockState.gas)
+      )
+    })
+
+    it('should set customData.limit when receiving a SET_CUSTOM_GAS_LIMIT action', () => {
+      assert.deepEqual(
+        GasReducer(mockState, {
+          type: SET_CUSTOM_GAS_LIMIT,
+          value: 9876,
+        }),
+        Object.assign({customData: {limit: 9876} }, mockState.gas)
+      )
+    })
+
+    it('should set customData.total when receiving a SET_CUSTOM_GAS_TOTAL action', () => {
+      assert.deepEqual(
+        GasReducer(mockState, {
+          type: SET_CUSTOM_GAS_TOTAL,
+          value: 10000,
+        }),
+        Object.assign({customData: {total: 10000} }, mockState.gas)
+      )
+    })
+
+    it('should set priceAndTimeEstimatesLastRetrieved when receiving a SET_API_ESTIMATES_LAST_RETRIEVED action', () => {
+      assert.deepEqual(
+        GasReducer(mockState, {
+          type: SET_API_ESTIMATES_LAST_RETRIEVED,
+          value: 1500000000000,
+        }),
+        Object.assign({ priceAndTimeEstimatesLastRetrieved: 1500000000000 }, mockState.gas)
+      )
+    })
+
+    it('should set priceAndTimeEstimatesLastRetrieved when receiving a SET_BASIC_API_ESTIMATES_LAST_RETRIEVED action', () => {
+      assert.deepEqual(
+        GasReducer(mockState, {
+          type: SET_BASIC_API_ESTIMATES_LAST_RETRIEVED,
+          value: 1700000000000,
+        }),
+        Object.assign({ basicPriceAndTimeEstimatesLastRetrieved: 1700000000000 }, mockState.gas)
+      )
+    })
+
+    it('should set errors when receiving a SET_CUSTOM_GAS_ERRORS action', () => {
+      assert.deepEqual(
+        GasReducer(mockState, {
+          type: SET_CUSTOM_GAS_ERRORS,
+          value: { someError: 'error_error' },
+        }),
+        Object.assign({errors: {someError: 'error_error'} }, mockState.gas)
+      )
+    })
+
+    it('should return the initial state in response to a RESET_CUSTOM_GAS_STATE action', () => {
+      assert.deepEqual(
+        GasReducer(mockState, {
+          type: RESET_CUSTOM_GAS_STATE,
+        }),
+        Object.assign({}, initState)
+      )
+    })
+  })
+
+  describe('basicGasEstimatesLoadingStarted', () => {
+    it('should create the correct action', () => {
+      assert.deepEqual(
+        basicGasEstimatesLoadingStarted(),
+        { type: BASIC_GAS_ESTIMATE_LOADING_STARTED }
+      )
+    })
+  })
+
+  describe('basicGasEstimatesLoadingFinished', () => {
+    it('should create the correct action', () => {
+      assert.deepEqual(
+        basicGasEstimatesLoadingFinished(),
+        { type: BASIC_GAS_ESTIMATE_LOADING_FINISHED }
+      )
+    })
+  })
+
+  describe('fetchBasicGasEstimates', () => {
+    const mockDistpatch = sinon.spy()
+    it('should call fetch with the expected params', async () => {
+      await fetchBasicGasEstimates()(mockDistpatch, () => ({ gas: Object.assign(
+        {},
+        initState,
+        { basicPriceAEstimatesLastRetrieved: 1000000 }
+      ) }))
+      assert.deepEqual(
+        mockDistpatch.getCall(0).args,
+        [{ type: BASIC_GAS_ESTIMATE_LOADING_STARTED} ]
+      )
+      assert.deepEqual(
+        global.fetch.getCall(0).args,
+        [
+          'https://dev.blockscale.net/api/gasexpress.json',
+          {
+            'headers': {},
+            'referrer': 'https://dev.blockscale.net/api/',
+            'referrerPolicy': 'no-referrer-when-downgrade',
+            'body': null,
+            'method': 'GET',
+            'mode': 'cors',
+          },
+        ]
+      )
+
+      assert.deepEqual(
+        mockDistpatch.getCall(1).args,
+        [{ type: SET_BASIC_PRICE_ESTIMATES_LAST_RETRIEVED, value: 2000000 } ]
+      )
+
+      assert.deepEqual(
+        mockDistpatch.getCall(2).args,
+        [{
+          type: SET_BASIC_GAS_ESTIMATE_DATA,
+          value: {
+            average: 20,
+            blockTime: 'mockBlock_time',
+            blockNum: 'mockBlockNum',
+            fast: 30,
+            fastest: 40,
+            safeLow: 10,
+          },
+        }]
+      )
+      assert.deepEqual(
+        mockDistpatch.getCall(3).args,
+        [{ type: BASIC_GAS_ESTIMATE_LOADING_FINISHED }]
+      )
+    })
+  })
+
+  describe('fetchBasicGasAndTimeEstimates', () => {
+    const mockDistpatch = sinon.spy()
+    it('should call fetch with the expected params', async () => {
+      await fetchBasicGasAndTimeEstimates()(mockDistpatch, () => ({ gas: Object.assign(
+        {},
+        initState,
+        { basicPriceAndTimeEstimatesLastRetrieved: 1000000 }
+      ) }))
+      assert.deepEqual(
+        mockDistpatch.getCall(0).args,
+        [{ type: BASIC_GAS_ESTIMATE_LOADING_STARTED} ]
+      )
+      assert.deepEqual(
+        global.fetch.getCall(0).args,
+        [
+          'https://ethgasstation.info/json/ethgasAPI.json',
+          {
+            'headers': {},
+            'referrer': 'http://ethgasstation.info/json/',
+            'referrerPolicy': 'no-referrer-when-downgrade',
+            'body': null,
+            'method': 'GET',
+            'mode': 'cors',
+          },
+        ]
+      )
+
+      assert.deepEqual(
+        mockDistpatch.getCall(1).args,
+        [{ type: SET_BASIC_API_ESTIMATES_LAST_RETRIEVED, value: 2000000 } ]
+      )
+
+      assert.deepEqual(
+        mockDistpatch.getCall(2).args,
+        [{
+          type: SET_BASIC_GAS_ESTIMATE_DATA,
+          value: {
+            average: 2,
+            avgWait: 'mockAvgWait',
+            blockTime: 'mockBlock_time',
+            blockNum: 'mockBlockNum',
+            fast: 3,
+            fastest: 4,
+            fastestWait: 'mockFastestWait',
+            fastWait: 'mockFastWait',
+            safeLow: 1,
+            safeLowWait: 'mockSafeLowWait',
+            speed: 'mockSpeed',
+          },
+        }]
+      )
+      assert.deepEqual(
+        mockDistpatch.getCall(3).args,
+        [{ type: BASIC_GAS_ESTIMATE_LOADING_FINISHED }]
+      )
+    })
+  })
+
+  describe('fetchGasEstimates', () => {
+    const mockDistpatch = sinon.spy()
+
+    beforeEach(() => {
+      mockDistpatch.resetHistory()
+    })
+
+    it('should call fetch with the expected params', async () => {
+      global.fetch.resetHistory()
+      await fetchGasEstimates(5)(mockDistpatch, () => ({ gas: Object.assign(
+        {},
+        initState,
+        { priceAndTimeEstimatesLastRetrieved: 1000000 }
+      ) }))
+      assert.deepEqual(
+        mockDistpatch.getCall(0).args,
+        [{ type: GAS_ESTIMATE_LOADING_STARTED} ]
+      )
+      assert.deepEqual(
+        global.fetch.getCall(0).args,
+        [
+          'https://ethgasstation.info/json/predictTable.json',
+          {
+            'headers': {},
+            'referrer': 'http://ethgasstation.info/json/',
+            'referrerPolicy': 'no-referrer-when-downgrade',
+            'body': null,
+            'method': 'GET',
+            'mode': 'cors',
+          },
+        ]
+      )
+
+      assert.deepEqual(
+        mockDistpatch.getCall(1).args,
+        [{ type: SET_API_ESTIMATES_LAST_RETRIEVED, value: 2000000 }]
+      )
+
+      const { type: thirdDispatchCallType, value: priceAndTimeEstimateResult } = mockDistpatch.getCall(2).args[0]
+      assert.equal(thirdDispatchCallType, SET_PRICE_AND_TIME_ESTIMATES)
+      assert(priceAndTimeEstimateResult.length < mockPredictTableResponse.length * 3 - 2)
+      assert(!priceAndTimeEstimateResult.find(d => d.expectedTime > 100))
+      assert(!priceAndTimeEstimateResult.find((d, i, a) => a[a + 1] && d.expectedTime > a[a + 1].expectedTime))
+      assert(!priceAndTimeEstimateResult.find((d, i, a) => a[a + 1] && d.gasprice > a[a + 1].gasprice))
+
+      assert.deepEqual(
+        mockDistpatch.getCall(3).args,
+        [{ type: GAS_ESTIMATE_LOADING_FINISHED }]
+      )
+    })
+
+    it('should not call fetch if the estimates were retrieved < 75000 ms ago', async () => {
+      global.fetch.resetHistory()
+      await fetchGasEstimates(5)(mockDistpatch, () => ({ gas: Object.assign(
+        {},
+        initState,
+        {
+          priceAndTimeEstimatesLastRetrieved: Date.now(),
+          priceAndTimeEstimates: [{
+            expectedTime: '10',
+            expectedWait: 2,
+            gasprice: 50,
+          }],
+        }
+      ) }))
+      assert.deepEqual(
+        mockDistpatch.getCall(0).args,
+        [{ type: GAS_ESTIMATE_LOADING_STARTED} ]
+      )
+      assert.equal(global.fetch.callCount, 0)
+
+      assert.deepEqual(
+        mockDistpatch.getCall(1).args,
+        [{
+          type: SET_PRICE_AND_TIME_ESTIMATES,
+          value: [
+            {
+              expectedTime: '10',
+              expectedWait: 2,
+              gasprice: 50,
+            },
+          ],
+
+        }]
+      )
+      assert.deepEqual(
+        mockDistpatch.getCall(2).args,
+        [{ type: GAS_ESTIMATE_LOADING_FINISHED }]
+      )
+    })
+  })
+
+  describe('gasEstimatesLoadingStarted', () => {
+    it('should create the correct action', () => {
+      assert.deepEqual(
+        gasEstimatesLoadingStarted(),
+        { type: GAS_ESTIMATE_LOADING_STARTED }
+      )
+    })
+  })
+
+  describe('gasEstimatesLoadingFinished', () => {
+    it('should create the correct action', () => {
+      assert.deepEqual(
+        gasEstimatesLoadingFinished(),
+        { type: GAS_ESTIMATE_LOADING_FINISHED }
+      )
+    })
+  })
+
+  describe('setPricesAndTimeEstimates', () => {
+    it('should create the correct action', () => {
+      assert.deepEqual(
+        setPricesAndTimeEstimates('mockPricesAndTimeEstimates'),
+        { type: SET_PRICE_AND_TIME_ESTIMATES, value: 'mockPricesAndTimeEstimates' }
+      )
+    })
+  })
+
+  describe('setBasicGasEstimateData', () => {
+    it('should create the correct action', () => {
+      assert.deepEqual(
+        setBasicGasEstimateData('mockBasicEstimatData'),
+        { type: SET_BASIC_GAS_ESTIMATE_DATA, value: 'mockBasicEstimatData' }
+      )
+    })
+  })
+
+  describe('setCustomGasPrice', () => {
+    it('should create the correct action', () => {
+      assert.deepEqual(
+        setCustomGasPrice('mockCustomGasPrice'),
+        { type: SET_CUSTOM_GAS_PRICE, value: 'mockCustomGasPrice' }
+      )
+    })
+  })
+
+  describe('setCustomGasLimit', () => {
+    it('should create the correct action', () => {
+      assert.deepEqual(
+        setCustomGasLimit('mockCustomGasLimit'),
+        { type: SET_CUSTOM_GAS_LIMIT, value: 'mockCustomGasLimit' }
+      )
+    })
+  })
+
+  describe('setCustomGasTotal', () => {
+    it('should create the correct action', () => {
+      assert.deepEqual(
+        setCustomGasTotal('mockCustomGasTotal'),
+        { type: SET_CUSTOM_GAS_TOTAL, value: 'mockCustomGasTotal' }
+      )
+    })
+  })
+
+  describe('setCustomGasErrors', () => {
+    it('should create the correct action', () => {
+      assert.deepEqual(
+        setCustomGasErrors('mockErrorObject'),
+        { type: SET_CUSTOM_GAS_ERRORS, value: 'mockErrorObject' }
+      )
+    })
+  })
+
+  describe('setApiEstimatesLastRetrieved', () => {
+    it('should create the correct action', () => {
+      assert.deepEqual(
+        setApiEstimatesLastRetrieved(1234),
+        { type: SET_API_ESTIMATES_LAST_RETRIEVED, value: 1234 }
+      )
+    })
+  })
+
+  describe('resetCustomGasState', () => {
+    it('should create the correct action', () => {
+      assert.deepEqual(
+        resetCustomGasState(),
+        { type: RESET_CUSTOM_GAS_STATE }
+      )
+    })
+  })
+
+})
diff --git a/ui/app/ducks/gas/gas.duck.js b/ui/app/ducks/gas/gas.duck.js
new file mode 100644
index 000000000..0a571a78e
--- /dev/null
+++ b/ui/app/ducks/gas/gas.duck.js
@@ -0,0 +1,517 @@
+import { clone, uniqBy, flatten } from 'ramda'
+import BigNumber from 'bignumber.js'
+import {
+  loadLocalStorageData,
+  saveLocalStorageData,
+} from '../../../lib/local-storage-helpers'
+import {
+  decGWEIToHexWEI,
+} from '../../helpers/utils/conversions.util'
+
+// Actions
+const BASIC_GAS_ESTIMATE_LOADING_FINISHED = 'metamask/gas/BASIC_GAS_ESTIMATE_LOADING_FINISHED'
+const BASIC_GAS_ESTIMATE_LOADING_STARTED = 'metamask/gas/BASIC_GAS_ESTIMATE_LOADING_STARTED'
+const GAS_ESTIMATE_LOADING_FINISHED = 'metamask/gas/GAS_ESTIMATE_LOADING_FINISHED'
+const GAS_ESTIMATE_LOADING_STARTED = 'metamask/gas/GAS_ESTIMATE_LOADING_STARTED'
+const RESET_CUSTOM_GAS_STATE = 'metamask/gas/RESET_CUSTOM_GAS_STATE'
+const RESET_CUSTOM_DATA = 'metamask/gas/RESET_CUSTOM_DATA'
+const SET_BASIC_GAS_ESTIMATE_DATA = 'metamask/gas/SET_BASIC_GAS_ESTIMATE_DATA'
+const SET_CUSTOM_GAS_ERRORS = 'metamask/gas/SET_CUSTOM_GAS_ERRORS'
+const SET_CUSTOM_GAS_LIMIT = 'metamask/gas/SET_CUSTOM_GAS_LIMIT'
+const SET_CUSTOM_GAS_PRICE = 'metamask/gas/SET_CUSTOM_GAS_PRICE'
+const SET_CUSTOM_GAS_TOTAL = 'metamask/gas/SET_CUSTOM_GAS_TOTAL'
+const SET_PRICE_AND_TIME_ESTIMATES = 'metamask/gas/SET_PRICE_AND_TIME_ESTIMATES'
+const SET_API_ESTIMATES_LAST_RETRIEVED = 'metamask/gas/SET_API_ESTIMATES_LAST_RETRIEVED'
+const SET_BASIC_API_ESTIMATES_LAST_RETRIEVED = 'metamask/gas/SET_BASIC_API_ESTIMATES_LAST_RETRIEVED'
+const SET_BASIC_PRICE_ESTIMATES_LAST_RETRIEVED = 'metamask/gas/SET_BASIC_PRICE_ESTIMATES_LAST_RETRIEVED'
+
+// TODO: determine if this approach to initState is consistent with conventional ducks pattern
+const initState = {
+  customData: {
+    price: null,
+    limit: null,
+  },
+  basicEstimates: {
+    average: null,
+    fastestWait: null,
+    fastWait: null,
+    fast: null,
+    safeLowWait: null,
+    blockNum: null,
+    avgWait: null,
+    blockTime: null,
+    speed: null,
+    fastest: null,
+    safeLow: null,
+  },
+  basicEstimateIsLoading: true,
+  gasEstimatesLoading: true,
+  priceAndTimeEstimates: [],
+  basicPriceAndTimeEstimates: [],
+  priceAndTimeEstimatesLastRetrieved: 0,
+  basicPriceAndTimeEstimatesLastRetrieved: 0,
+  basicPriceEstimatesLastRetrieved: 0,
+  errors: {},
+}
+
+// Reducer
+export default function reducer ({ gas: gasState = initState }, action = {}) {
+  const newState = clone(gasState)
+
+  switch (action.type) {
+    case BASIC_GAS_ESTIMATE_LOADING_STARTED:
+      return {
+        ...newState,
+        basicEstimateIsLoading: true,
+      }
+    case BASIC_GAS_ESTIMATE_LOADING_FINISHED:
+      return {
+        ...newState,
+        basicEstimateIsLoading: false,
+      }
+    case GAS_ESTIMATE_LOADING_STARTED:
+      return {
+        ...newState,
+        gasEstimatesLoading: true,
+      }
+    case GAS_ESTIMATE_LOADING_FINISHED:
+      return {
+        ...newState,
+        gasEstimatesLoading: false,
+      }
+    case SET_BASIC_GAS_ESTIMATE_DATA:
+      return {
+        ...newState,
+        basicEstimates: action.value,
+      }
+    case SET_CUSTOM_GAS_PRICE:
+      return {
+        ...newState,
+        customData: {
+          ...newState.customData,
+          price: action.value,
+        },
+      }
+    case SET_CUSTOM_GAS_LIMIT:
+      return {
+        ...newState,
+        customData: {
+          ...newState.customData,
+          limit: action.value,
+        },
+      }
+    case SET_CUSTOM_GAS_TOTAL:
+      return {
+        ...newState,
+        customData: {
+          ...newState.customData,
+          total: action.value,
+        },
+      }
+    case SET_PRICE_AND_TIME_ESTIMATES:
+      return {
+        ...newState,
+        priceAndTimeEstimates: action.value,
+      }
+    case SET_CUSTOM_GAS_ERRORS:
+      return {
+        ...newState,
+        errors: {
+          ...newState.errors,
+          ...action.value,
+        },
+      }
+    case SET_API_ESTIMATES_LAST_RETRIEVED:
+      return {
+        ...newState,
+        priceAndTimeEstimatesLastRetrieved: action.value,
+      }
+    case SET_BASIC_API_ESTIMATES_LAST_RETRIEVED:
+      return {
+        ...newState,
+        basicPriceAndTimeEstimatesLastRetrieved: action.value,
+      }
+    case SET_BASIC_PRICE_ESTIMATES_LAST_RETRIEVED:
+      return {
+        ...newState,
+        basicPriceEstimatesLastRetrieved: action.value,
+      }
+    case RESET_CUSTOM_DATA:
+      return {
+        ...newState,
+        customData: clone(initState.customData),
+      }
+    case RESET_CUSTOM_GAS_STATE:
+      return clone(initState)
+    default:
+      return newState
+  }
+}
+
+// Action Creators
+export function basicGasEstimatesLoadingStarted () {
+  return {
+    type: BASIC_GAS_ESTIMATE_LOADING_STARTED,
+  }
+}
+
+export function basicGasEstimatesLoadingFinished () {
+  return {
+    type: BASIC_GAS_ESTIMATE_LOADING_FINISHED,
+  }
+}
+
+export function gasEstimatesLoadingStarted () {
+  return {
+    type: GAS_ESTIMATE_LOADING_STARTED,
+  }
+}
+
+export function gasEstimatesLoadingFinished () {
+  return {
+    type: GAS_ESTIMATE_LOADING_FINISHED,
+  }
+}
+
+export function fetchBasicGasEstimates () {
+  return (dispatch, getState) => {
+    const {
+      basicPriceEstimatesLastRetrieved,
+      basicPriceAndTimeEstimates,
+    } = getState().gas
+    const timeLastRetrieved = basicPriceEstimatesLastRetrieved || loadLocalStorageData('BASIC_PRICE_ESTIMATES_LAST_RETRIEVED') || 0
+
+    dispatch(basicGasEstimatesLoadingStarted())
+
+    const promiseToFetch = Date.now() - timeLastRetrieved > 75000
+    ? fetch('https://dev.blockscale.net/api/gasexpress.json', {
+      'headers': {},
+      'referrer': 'https://dev.blockscale.net/api/',
+      'referrerPolicy': 'no-referrer-when-downgrade',
+      'body': null,
+      'method': 'GET',
+      'mode': 'cors'}
+    )
+      .then(r => r.json())
+      .then(({
+        safeLow,
+        standard: average,
+        fast,
+        fastest,
+        block_time: blockTime,
+        blockNum,
+      }) => {
+        const basicEstimates = {
+          safeLow,
+          average,
+          fast,
+          fastest,
+          blockTime,
+          blockNum,
+        }
+
+        const timeRetrieved = Date.now()
+        dispatch(setBasicPriceEstimatesLastRetrieved(timeRetrieved))
+        saveLocalStorageData(timeRetrieved, 'BASIC_PRICE_ESTIMATES_LAST_RETRIEVED')
+        saveLocalStorageData(basicEstimates, 'BASIC_PRICE_ESTIMATES')
+
+        return basicEstimates
+      })
+    : Promise.resolve(basicPriceAndTimeEstimates.length
+        ? basicPriceAndTimeEstimates
+        : loadLocalStorageData('BASIC_PRICE_ESTIMATES')
+      )
+
+    return promiseToFetch.then(basicEstimates => {
+      dispatch(setBasicGasEstimateData(basicEstimates))
+      dispatch(basicGasEstimatesLoadingFinished())
+      return basicEstimates
+    })
+  }
+}
+
+export function fetchBasicGasAndTimeEstimates () {
+  return (dispatch, getState) => {
+    const {
+      basicPriceAndTimeEstimatesLastRetrieved,
+      basicPriceAndTimeEstimates,
+    } = getState().gas
+    const timeLastRetrieved = basicPriceAndTimeEstimatesLastRetrieved || loadLocalStorageData('BASIC_GAS_AND_TIME_API_ESTIMATES_LAST_RETRIEVED') || 0
+
+    dispatch(basicGasEstimatesLoadingStarted())
+
+    const promiseToFetch = Date.now() - timeLastRetrieved > 75000
+      ? fetch('https://ethgasstation.info/json/ethgasAPI.json', {
+        'headers': {},
+        'referrer': 'http://ethgasstation.info/json/',
+        'referrerPolicy': 'no-referrer-when-downgrade',
+        'body': null,
+        'method': 'GET',
+        'mode': 'cors'}
+      )
+        .then(r => r.json())
+        .then(({
+          average: averageTimes10,
+          avgWait,
+          block_time: blockTime,
+          blockNum,
+          fast: fastTimes10,
+          fastest: fastestTimes10,
+          fastestWait,
+          fastWait,
+          safeLow: safeLowTimes10,
+          safeLowWait,
+          speed,
+        }) => {
+          const [average, fast, fastest, safeLow] = [
+            averageTimes10,
+            fastTimes10,
+            fastestTimes10,
+            safeLowTimes10,
+          ].map(price => (new BigNumber(price)).div(10).toNumber())
+
+          const basicEstimates = {
+            average,
+            avgWait,
+            blockTime,
+            blockNum,
+            fast,
+            fastest,
+            fastestWait,
+            fastWait,
+            safeLow,
+            safeLowWait,
+            speed,
+          }
+
+          const timeRetrieved = Date.now()
+          dispatch(setBasicApiEstimatesLastRetrieved(timeRetrieved))
+          saveLocalStorageData(timeRetrieved, 'BASIC_GAS_AND_TIME_API_ESTIMATES_LAST_RETRIEVED')
+          saveLocalStorageData(basicEstimates, 'BASIC_GAS_AND_TIME_API_ESTIMATES')
+
+          return basicEstimates
+        })
+      : Promise.resolve(basicPriceAndTimeEstimates.length
+          ? basicPriceAndTimeEstimates
+          : loadLocalStorageData('BASIC_GAS_AND_TIME_API_ESTIMATES')
+        )
+
+      return promiseToFetch.then(basicEstimates => {
+        dispatch(setBasicGasEstimateData(basicEstimates))
+        dispatch(basicGasEstimatesLoadingFinished())
+        return basicEstimates
+      })
+  }
+}
+
+function extrapolateY ({ higherY, lowerY, higherX, lowerX, xForExtrapolation }) {
+  higherY = new BigNumber(higherY, 10)
+  lowerY = new BigNumber(lowerY, 10)
+  higherX = new BigNumber(higherX, 10)
+  lowerX = new BigNumber(lowerX, 10)
+  xForExtrapolation = new BigNumber(xForExtrapolation, 10)
+  const slope = (higherY.minus(lowerY)).div(higherX.minus(lowerX))
+  const newTimeEstimate = slope.times(higherX.minus(xForExtrapolation)).minus(higherY).negated()
+
+  return Number(newTimeEstimate.toPrecision(10))
+}
+
+function getRandomArbitrary (min, max) {
+  min = new BigNumber(min, 10)
+  max = new BigNumber(max, 10)
+  const random = new BigNumber(String(Math.random()), 10)
+  return new BigNumber(random.times(max.minus(min)).plus(min)).toPrecision(10)
+}
+
+function calcMedian (list) {
+  const medianPos = (Math.floor(list.length / 2) + Math.ceil(list.length / 2)) / 2
+  return medianPos === Math.floor(medianPos)
+    ? (list[medianPos - 1] + list[medianPos]) / 2
+    : list[Math.floor(medianPos)]
+}
+
+function quartiles (data) {
+  const lowerHalf = data.slice(0, Math.floor(data.length / 2))
+  const upperHalf = data.slice(Math.floor(data.length / 2) + (data.length % 2 === 0 ? 0 : 1))
+  const median = calcMedian(data)
+  const lowerQuartile = calcMedian(lowerHalf)
+  const upperQuartile = calcMedian(upperHalf)
+  return {
+    median,
+    lowerQuartile,
+    upperQuartile,
+  }
+}
+
+function inliersByIQR (data, prop) {
+  const { lowerQuartile, upperQuartile } = quartiles(data.map(d => prop ? d[prop] : d))
+  const IQR = upperQuartile - lowerQuartile
+  const lowerBound = lowerQuartile - 1.5 * IQR
+  const upperBound = upperQuartile + 1.5 * IQR
+  return data.filter(d => {
+    const value = prop ? d[prop] : d
+    return value >= lowerBound && value <= upperBound
+  })
+}
+
+export function fetchGasEstimates (blockTime) {
+  return (dispatch, getState) => {
+    const {
+      priceAndTimeEstimatesLastRetrieved,
+      priceAndTimeEstimates,
+    } = getState().gas
+    const timeLastRetrieved = priceAndTimeEstimatesLastRetrieved || loadLocalStorageData('GAS_API_ESTIMATES_LAST_RETRIEVED') || 0
+
+    dispatch(gasEstimatesLoadingStarted())
+
+    const promiseToFetch = Date.now() - timeLastRetrieved > 75000
+      ? fetch('https://ethgasstation.info/json/predictTable.json', {
+          'headers': {},
+          'referrer': 'http://ethgasstation.info/json/',
+          'referrerPolicy': 'no-referrer-when-downgrade',
+          'body': null,
+          'method': 'GET',
+          'mode': 'cors'}
+        )
+        .then(r => r.json())
+        .then(r => {
+          const estimatedPricesAndTimes = r.map(({ expectedTime, expectedWait, gasprice }) => ({ expectedTime, expectedWait, gasprice }))
+          const estimatedTimeWithUniquePrices = uniqBy(({ expectedTime }) => expectedTime, estimatedPricesAndTimes)
+
+          const withSupplementalTimeEstimates = flatten(estimatedTimeWithUniquePrices.map(({ expectedWait, gasprice }, i, arr) => {
+            const next = arr[i + 1]
+            if (!next) {
+              return [{ expectedWait, gasprice }]
+            } else {
+              const supplementalPrice = getRandomArbitrary(gasprice, next.gasprice)
+              const supplementalTime = extrapolateY({
+                higherY: next.expectedWait,
+                lowerY: expectedWait,
+                higherX: next.gasprice,
+                lowerX: gasprice,
+                xForExtrapolation: supplementalPrice,
+              })
+              const supplementalPrice2 = getRandomArbitrary(supplementalPrice, next.gasprice)
+              const supplementalTime2 = extrapolateY({
+                higherY: next.expectedWait,
+                lowerY: supplementalTime,
+                higherX: next.gasprice,
+                lowerX: supplementalPrice,
+                xForExtrapolation: supplementalPrice2,
+              })
+              return [
+                { expectedWait, gasprice },
+                { expectedWait: supplementalTime, gasprice: supplementalPrice },
+                { expectedWait: supplementalTime2, gasprice: supplementalPrice2 },
+              ]
+            }
+          }))
+          const withOutliersRemoved = inliersByIQR(withSupplementalTimeEstimates.slice(0).reverse(), 'expectedWait').reverse()
+          const timeMappedToSeconds = withOutliersRemoved.map(({ expectedWait, gasprice }) => {
+            const expectedTime = (new BigNumber(expectedWait)).times(Number(blockTime), 10).toNumber()
+            return {
+              expectedTime,
+              gasprice: (new BigNumber(gasprice, 10).toNumber()),
+            }
+          })
+
+          const timeRetrieved = Date.now()
+          dispatch(setApiEstimatesLastRetrieved(timeRetrieved))
+          saveLocalStorageData(timeRetrieved, 'GAS_API_ESTIMATES_LAST_RETRIEVED')
+          saveLocalStorageData(timeMappedToSeconds, 'GAS_API_ESTIMATES')
+
+          return timeMappedToSeconds
+        })
+      : Promise.resolve(priceAndTimeEstimates.length
+          ? priceAndTimeEstimates
+          : loadLocalStorageData('GAS_API_ESTIMATES')
+        )
+
+      return promiseToFetch.then(estimates => {
+        dispatch(setPricesAndTimeEstimates(estimates))
+        dispatch(gasEstimatesLoadingFinished())
+      })
+  }
+}
+
+export function setCustomGasPriceForRetry (newPrice) {
+  return (dispatch) => {
+    if (newPrice !== '0x0') {
+      dispatch(setCustomGasPrice(newPrice))
+    } else {
+      const { fast } = loadLocalStorageData('BASIC_PRICE_ESTIMATES')
+      dispatch(setCustomGasPrice(decGWEIToHexWEI(fast)))
+    }
+  }
+}
+
+export function setBasicGasEstimateData (basicGasEstimateData) {
+  return {
+    type: SET_BASIC_GAS_ESTIMATE_DATA,
+    value: basicGasEstimateData,
+  }
+}
+
+export function setPricesAndTimeEstimates (estimatedPricesAndTimes) {
+  return {
+    type: SET_PRICE_AND_TIME_ESTIMATES,
+    value: estimatedPricesAndTimes,
+  }
+}
+
+export function setCustomGasPrice (newPrice) {
+  return {
+    type: SET_CUSTOM_GAS_PRICE,
+    value: newPrice,
+  }
+}
+
+export function setCustomGasLimit (newLimit) {
+  return {
+    type: SET_CUSTOM_GAS_LIMIT,
+    value: newLimit,
+  }
+}
+
+export function setCustomGasTotal (newTotal) {
+  return {
+    type: SET_CUSTOM_GAS_TOTAL,
+    value: newTotal,
+  }
+}
+
+export function setCustomGasErrors (newErrors) {
+  return {
+    type: SET_CUSTOM_GAS_ERRORS,
+    value: newErrors,
+  }
+}
+
+export function setApiEstimatesLastRetrieved (retrievalTime) {
+  return {
+    type: SET_API_ESTIMATES_LAST_RETRIEVED,
+    value: retrievalTime,
+  }
+}
+
+export function setBasicApiEstimatesLastRetrieved (retrievalTime) {
+  return {
+    type: SET_BASIC_API_ESTIMATES_LAST_RETRIEVED,
+    value: retrievalTime,
+  }
+}
+
+export function setBasicPriceEstimatesLastRetrieved (retrievalTime) {
+  return {
+    type: SET_BASIC_PRICE_ESTIMATES_LAST_RETRIEVED,
+    value: retrievalTime,
+  }
+}
+
+export function resetCustomGasState () {
+  return { type: RESET_CUSTOM_GAS_STATE }
+}
+
+export function resetCustomData () {
+  return { type: RESET_CUSTOM_DATA }
+}