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-rw-r--r--packages/asset-buyer/CHANGELOG.json8
-rw-r--r--packages/asset-buyer/src/errors.ts22
-rw-r--r--packages/asset-buyer/src/index.ts1
-rw-r--r--packages/asset-buyer/src/types.ts2
-rw-r--r--packages/asset-buyer/src/utils/buy_quote_calculator.ts14
-rw-r--r--packages/asset-buyer/test/buy_quote_calculator_test.ts143
-rw-r--r--packages/asset-buyer/test/utils/test_helpers.ts26
-rw-r--r--packages/instant/src/constants.ts1
-rw-r--r--packages/instant/src/util/asset.ts21
-rw-r--r--packages/instant/src/util/buy_quote_updater.ts7
-rw-r--r--packages/instant/test/util/asset.test.ts43
-rw-r--r--packages/monorepo-scripts/src/doc_gen_configs.ts1
12 files changed, 272 insertions, 17 deletions
diff --git a/packages/asset-buyer/CHANGELOG.json b/packages/asset-buyer/CHANGELOG.json
index 470d9b03b..44837d040 100644
--- a/packages/asset-buyer/CHANGELOG.json
+++ b/packages/asset-buyer/CHANGELOG.json
@@ -1,5 +1,13 @@
[
{
+ "version": "4.0.0",
+ "changes": [
+ {
+ "note": "Raise custom InsufficientAssetLiquidityError error with amountAvailableToFill attribute"
+ }
+ ]
+ },
+ {
"version": "3.0.4",
"changes": [
{
diff --git a/packages/asset-buyer/src/errors.ts b/packages/asset-buyer/src/errors.ts
new file mode 100644
index 000000000..ec5fe548c
--- /dev/null
+++ b/packages/asset-buyer/src/errors.ts
@@ -0,0 +1,22 @@
+import { BigNumber } from '@0x/utils';
+
+import { AssetBuyerError } from './types';
+
+/**
+ * Error class representing insufficient asset liquidity
+ */
+export class InsufficientAssetLiquidityError extends Error {
+ /**
+ * The amount availabe to fill (in base units) factoring in slippage.
+ */
+ public amountAvailableToFill: BigNumber;
+ /**
+ * @param amountAvailableToFill The amount availabe to fill (in base units) factoring in slippage
+ */
+ constructor(amountAvailableToFill: BigNumber) {
+ super(AssetBuyerError.InsufficientAssetLiquidity);
+ this.amountAvailableToFill = amountAvailableToFill;
+ // Setting prototype so instanceof works. See https://github.com/Microsoft/TypeScript/wiki/Breaking-Changes#extending-built-ins-like-error-array-and-map-may-no-longer-work
+ Object.setPrototypeOf(this, InsufficientAssetLiquidityError.prototype);
+ }
+}
diff --git a/packages/asset-buyer/src/index.ts b/packages/asset-buyer/src/index.ts
index 8418edb42..a42d7e272 100644
--- a/packages/asset-buyer/src/index.ts
+++ b/packages/asset-buyer/src/index.ts
@@ -9,6 +9,7 @@ export { SignedOrder } from '@0x/types';
export { BigNumber } from '@0x/utils';
export { AssetBuyer } from './asset_buyer';
+export { InsufficientAssetLiquidityError } from './errors';
export { BasicOrderProvider } from './order_providers/basic_order_provider';
export { StandardRelayerAPIOrderProvider } from './order_providers/standard_relayer_api_order_provider';
export {
diff --git a/packages/asset-buyer/src/types.ts b/packages/asset-buyer/src/types.ts
index 3b573edca..d5d6be695 100644
--- a/packages/asset-buyer/src/types.ts
+++ b/packages/asset-buyer/src/types.ts
@@ -102,7 +102,7 @@ export interface AssetBuyerOpts {
}
/**
- * Possible errors thrown by an AssetBuyer instance or associated static methods.
+ * Possible error messages thrown by an AssetBuyer instance or associated static methods.
*/
export enum AssetBuyerError {
NoEtherTokenContractFound = 'NO_ETHER_TOKEN_CONTRACT_FOUND',
diff --git a/packages/asset-buyer/src/utils/buy_quote_calculator.ts b/packages/asset-buyer/src/utils/buy_quote_calculator.ts
index b15b880c2..fcded6ab1 100644
--- a/packages/asset-buyer/src/utils/buy_quote_calculator.ts
+++ b/packages/asset-buyer/src/utils/buy_quote_calculator.ts
@@ -3,6 +3,7 @@ import { BigNumber } from '@0x/utils';
import * as _ from 'lodash';
import { constants } from '../constants';
+import { InsufficientAssetLiquidityError } from '../errors';
import { AssetBuyerError, BuyQuote, BuyQuoteInfo, OrdersAndFillableAmounts } from '../types';
import { orderUtils } from './order_utils';
@@ -33,7 +34,18 @@ export const buyQuoteCalculator = {
});
// if we do not have enough orders to cover the desired assetBuyAmount, throw
if (remainingFillAmount.gt(constants.ZERO_AMOUNT)) {
- throw new Error(AssetBuyerError.InsufficientAssetLiquidity);
+ // We needed the amount they requested to buy, plus the amount for slippage
+ const totalAmountRequested = assetBuyAmount.plus(slippageBufferAmount);
+ const amountAbleToFill = totalAmountRequested.minus(remainingFillAmount);
+ // multiplierNeededWithSlippage represents what we need to multiply the assetBuyAmount by
+ // in order to get the total amount needed considering slippage
+ // i.e. if slippagePercent was 0.2 (20%), multiplierNeededWithSlippage would be 1.2
+ const multiplierNeededWithSlippage = new BigNumber(1).plus(slippagePercentage);
+ // Given amountAvailableToFillConsideringSlippage * multiplierNeededWithSlippage = amountAbleToFill
+ // We divide amountUnableToFill by multiplierNeededWithSlippage to determine amountAvailableToFillConsideringSlippage
+ const amountAvailableToFillConsideringSlippage = amountAbleToFill.div(multiplierNeededWithSlippage).floor();
+
+ throw new InsufficientAssetLiquidityError(amountAvailableToFillConsideringSlippage);
}
// if we are not buying ZRX:
// given the orders calculated above, find the fee-orders that cover the desired assetBuyAmount (with slippage)
diff --git a/packages/asset-buyer/test/buy_quote_calculator_test.ts b/packages/asset-buyer/test/buy_quote_calculator_test.ts
index a30017b72..fdc17ef25 100644
--- a/packages/asset-buyer/test/buy_quote_calculator_test.ts
+++ b/packages/asset-buyer/test/buy_quote_calculator_test.ts
@@ -1,4 +1,5 @@
import { orderFactory } from '@0x/order-utils/lib/src/order_factory';
+import { SignedOrder } from '@0x/types';
import { BigNumber } from '@0x/utils';
import * as chai from 'chai';
import * as _ from 'lodash';
@@ -8,6 +9,7 @@ import { AssetBuyerError, OrdersAndFillableAmounts } from '../src/types';
import { buyQuoteCalculator } from '../src/utils/buy_quote_calculator';
import { chaiSetup } from './utils/chai_setup';
+import { testHelpers } from './utils/test_helpers';
chaiSetup.configure();
const expect = chai.expect;
@@ -15,6 +17,10 @@ const expect = chai.expect;
// tslint:disable:custom-no-magic-numbers
describe('buyQuoteCalculator', () => {
describe('#calculate', () => {
+ let firstOrder: SignedOrder;
+ let firstRemainingFillAmount: BigNumber;
+ let secondOrder: SignedOrder;
+ let secondRemainingFillAmount: BigNumber;
let ordersAndFillableAmounts: OrdersAndFillableAmounts;
let smallFeeOrderAndFillableAmount: OrdersAndFillableAmounts;
let allFeeOrdersAndFillableAmounts: OrdersAndFillableAmounts;
@@ -24,18 +30,18 @@ describe('buyQuoteCalculator', () => {
// the second order has a rate of 2 makerAsset / WETH with a takerFee of 100 ZRX and has 200 / 200 makerAsset units left to fill (completely fillable)
// generate one order for fees
// the fee order has a rate of 1 ZRX / WETH with no taker fee and has 100 ZRX left to fill (completely fillable)
- const firstOrder = orderFactory.createSignedOrderFromPartial({
+ firstOrder = orderFactory.createSignedOrderFromPartial({
makerAssetAmount: new BigNumber(400),
takerAssetAmount: new BigNumber(100),
takerFee: new BigNumber(200),
});
- const firstRemainingFillAmount = new BigNumber(200);
- const secondOrder = orderFactory.createSignedOrderFromPartial({
+ firstRemainingFillAmount = new BigNumber(200);
+ secondOrder = orderFactory.createSignedOrderFromPartial({
makerAssetAmount: new BigNumber(200),
takerAssetAmount: new BigNumber(100),
takerFee: new BigNumber(100),
});
- const secondRemainingFillAmount = secondOrder.makerAssetAmount;
+ secondRemainingFillAmount = secondOrder.makerAssetAmount;
ordersAndFillableAmounts = {
orders: [firstOrder, secondOrder],
remainingFillableMakerAssetAmounts: [firstRemainingFillAmount, secondRemainingFillAmount],
@@ -61,18 +67,137 @@ describe('buyQuoteCalculator', () => {
],
};
});
- it('should throw if not enough maker asset liquidity', () => {
- // we have 400 makerAsset units available to fill but attempt to calculate a quote for 500 makerAsset units
+ describe('InsufficientLiquidityError', () => {
+ it('should throw if not enough maker asset liquidity (multiple orders)', () => {
+ // we have 400 makerAsset units available to fill but attempt to calculate a quote for 500 makerAsset units
+ const errorFunction = () => {
+ buyQuoteCalculator.calculate(
+ ordersAndFillableAmounts,
+ smallFeeOrderAndFillableAmount,
+ new BigNumber(500),
+ 0,
+ 0,
+ false,
+ );
+ };
+ testHelpers.expectInsufficientLiquidityError(expect, errorFunction, new BigNumber(400));
+ });
+ it('should throw if not enough maker asset liquidity (multiple orders with 20% slippage)', () => {
+ // we have 400 makerAsset units available to fill but attempt to calculate a quote for 500 makerAsset units
+ const errorFunction = () => {
+ buyQuoteCalculator.calculate(
+ ordersAndFillableAmounts,
+ smallFeeOrderAndFillableAmount,
+ new BigNumber(500),
+ 0,
+ 0.2,
+ false,
+ );
+ };
+ testHelpers.expectInsufficientLiquidityError(expect, errorFunction, new BigNumber(333));
+ });
+ it('should throw if not enough maker asset liquidity (multiple orders with 5% slippage)', () => {
+ // we have 400 makerAsset units available to fill but attempt to calculate a quote for 500 makerAsset units
+ const errorFunction = () => {
+ buyQuoteCalculator.calculate(
+ ordersAndFillableAmounts,
+ smallFeeOrderAndFillableAmount,
+ new BigNumber(600),
+ 0,
+ 0.05,
+ false,
+ );
+ };
+ testHelpers.expectInsufficientLiquidityError(expect, errorFunction, new BigNumber(380));
+ });
+ it('should throw if not enough maker asset liquidity (partially filled order)', () => {
+ const firstOrderAndFillableAmount: OrdersAndFillableAmounts = {
+ orders: [firstOrder],
+ remainingFillableMakerAssetAmounts: [firstRemainingFillAmount],
+ };
+
+ const errorFunction = () => {
+ buyQuoteCalculator.calculate(
+ firstOrderAndFillableAmount,
+ smallFeeOrderAndFillableAmount,
+ new BigNumber(201),
+ 0,
+ 0,
+ false,
+ );
+ };
+ testHelpers.expectInsufficientLiquidityError(expect, errorFunction, new BigNumber(200));
+ });
+ it('should throw if not enough maker asset liquidity (completely fillable order)', () => {
+ const completelyFillableOrder = orderFactory.createSignedOrderFromPartial({
+ makerAssetAmount: new BigNumber(123),
+ takerAssetAmount: new BigNumber(100),
+ takerFee: new BigNumber(200),
+ });
+ const completelyFillableOrdersAndFillableAmount: OrdersAndFillableAmounts = {
+ orders: [completelyFillableOrder],
+ remainingFillableMakerAssetAmounts: [completelyFillableOrder.makerAssetAmount],
+ };
+ const errorFunction = () => {
+ buyQuoteCalculator.calculate(
+ completelyFillableOrdersAndFillableAmount,
+ smallFeeOrderAndFillableAmount,
+ new BigNumber(124),
+ 0,
+ 0,
+ false,
+ );
+ };
+ testHelpers.expectInsufficientLiquidityError(expect, errorFunction, new BigNumber(123));
+ });
+ it('should throw with 1 amount available if no slippage', () => {
+ const smallOrder = orderFactory.createSignedOrderFromPartial({
+ makerAssetAmount: new BigNumber(1),
+ takerAssetAmount: new BigNumber(1),
+ takerFee: new BigNumber(0),
+ });
+ const errorFunction = () => {
+ buyQuoteCalculator.calculate(
+ { orders: [smallOrder], remainingFillableMakerAssetAmounts: [smallOrder.makerAssetAmount] },
+ smallFeeOrderAndFillableAmount,
+ new BigNumber(600),
+ 0,
+ 0,
+ false,
+ );
+ };
+ testHelpers.expectInsufficientLiquidityError(expect, errorFunction, new BigNumber(1));
+ });
+ it('should throw without amount available to fill if amount rounds to 0', () => {
+ const smallOrder = orderFactory.createSignedOrderFromPartial({
+ makerAssetAmount: new BigNumber(1),
+ takerAssetAmount: new BigNumber(1),
+ takerFee: new BigNumber(0),
+ });
+ const errorFunction = () => {
+ buyQuoteCalculator.calculate(
+ { orders: [smallOrder], remainingFillableMakerAssetAmounts: [smallOrder.makerAssetAmount] },
+ smallFeeOrderAndFillableAmount,
+ new BigNumber(600),
+ 0,
+ 0.2,
+ false,
+ );
+ };
+ testHelpers.expectInsufficientLiquidityError(expect, errorFunction, undefined);
+ });
+ });
+ it('should not throw if order is fillable', () => {
expect(() =>
buyQuoteCalculator.calculate(
ordersAndFillableAmounts,
- smallFeeOrderAndFillableAmount,
- new BigNumber(500),
+ allFeeOrdersAndFillableAmounts,
+ new BigNumber(300),
0,
0,
false,
),
- ).to.throw(AssetBuyerError.InsufficientAssetLiquidity);
+ ).to.not.throw();
});
it('should throw if not enough ZRX liquidity', () => {
// we request 300 makerAsset units but the ZRX order is only enough to fill the first order, which only has 200 makerAssetUnits available
diff --git a/packages/asset-buyer/test/utils/test_helpers.ts b/packages/asset-buyer/test/utils/test_helpers.ts
new file mode 100644
index 000000000..9c7c244af
--- /dev/null
+++ b/packages/asset-buyer/test/utils/test_helpers.ts
@@ -0,0 +1,26 @@
+import { BigNumber } from '@0x/utils';
+
+import { InsufficientAssetLiquidityError } from '../../src/errors';
+
+export const testHelpers = {
+ expectInsufficientLiquidityError: (
+ expect: Chai.ExpectStatic,
+ functionWhichTriggersError: () => void,
+ expectedAmountAvailableToFill?: BigNumber,
+ ): void => {
+ let wasErrorThrown = false;
+ try {
+ functionWhichTriggersError();
+ } catch (e) {
+ wasErrorThrown = true;
+ expect(e).to.be.instanceOf(InsufficientAssetLiquidityError);
+ if (expectedAmountAvailableToFill) {
+ expect(e.amountAvailableToFill).to.be.bignumber.equal(expectedAmountAvailableToFill);
+ } else {
+ expect(e.amountAvailableToFill).to.be.undefined();
+ }
+ }
+
+ expect(wasErrorThrown).to.be.true();
+ },
+};
diff --git a/packages/instant/src/constants.ts b/packages/instant/src/constants.ts
index 22f0cb6a4..67558c84a 100644
--- a/packages/instant/src/constants.ts
+++ b/packages/instant/src/constants.ts
@@ -16,6 +16,7 @@ export const ONE_SECOND_MS = 1000;
export const ONE_MINUTE_MS = ONE_SECOND_MS * 60;
export const GIT_SHA = process.env.GIT_SHA;
export const NODE_ENV = process.env.NODE_ENV;
+export const SLIPPAGE_PERCENTAGE = 0.2;
export const NPM_PACKAGE_VERSION = process.env.NPM_PACKAGE_VERSION;
export const DEFAULT_UNKOWN_ASSET_NAME = '???';
export const ACCOUNT_UPDATE_INTERVAL_TIME_MS = ONE_SECOND_MS * 5;
diff --git a/packages/instant/src/util/asset.ts b/packages/instant/src/util/asset.ts
index faaeb7c22..b009a327f 100644
--- a/packages/instant/src/util/asset.ts
+++ b/packages/instant/src/util/asset.ts
@@ -1,8 +1,10 @@
-import { AssetBuyerError } from '@0x/asset-buyer';
+import { AssetBuyerError, InsufficientAssetLiquidityError } from '@0x/asset-buyer';
import { AssetProxyId, ObjectMap } from '@0x/types';
+import { BigNumber } from '@0x/utils';
+import { Web3Wrapper } from '@0x/web3-wrapper';
import * as _ from 'lodash';
-import { DEFAULT_UNKOWN_ASSET_NAME } from '../constants';
+import { BIG_NUMBER_ZERO, DEFAULT_UNKOWN_ASSET_NAME } from '../constants';
import { assetDataNetworkMapping } from '../data/asset_data_network_mapping';
import { Asset, AssetMetaData, ERC20Asset, Network, ZeroExInstantError } from '../types';
@@ -111,6 +113,21 @@ export const assetUtils = {
assetBuyerErrorMessage: (asset: ERC20Asset, error: Error): string | undefined => {
if (error.message === AssetBuyerError.InsufficientAssetLiquidity) {
const assetName = assetUtils.bestNameForAsset(asset, 'of this asset');
+ if (
+ error instanceof InsufficientAssetLiquidityError &&
+ error.amountAvailableToFill.greaterThan(BIG_NUMBER_ZERO)
+ ) {
+ const unitAmountAvailableToFill = Web3Wrapper.toUnitAmount(
+ error.amountAvailableToFill,
+ asset.metaData.decimals,
+ );
+ const roundedUnitAmountAvailableToFill = unitAmountAvailableToFill.round(2, BigNumber.ROUND_DOWN);
+
+ if (roundedUnitAmountAvailableToFill.greaterThan(BIG_NUMBER_ZERO)) {
+ return `There are only ${roundedUnitAmountAvailableToFill} ${assetName} available to buy`;
+ }
+ }
+
return `Not enough ${assetName} available`;
} else if (error.message === AssetBuyerError.InsufficientZrxLiquidity) {
return 'Not enough ZRX available';
diff --git a/packages/instant/src/util/buy_quote_updater.ts b/packages/instant/src/util/buy_quote_updater.ts
index 6191c92e3..37974e71c 100644
--- a/packages/instant/src/util/buy_quote_updater.ts
+++ b/packages/instant/src/util/buy_quote_updater.ts
@@ -5,6 +5,7 @@ import * as _ from 'lodash';
import { Dispatch } from 'redux';
import { oc } from 'ts-optchain';
+import { SLIPPAGE_PERCENTAGE } from '../constants';
import { Action, actions } from '../redux/actions';
import { AffiliateInfo, ERC20Asset, QuoteFetchOrigin } from '../types';
import { analytics } from '../util/analytics';
@@ -33,8 +34,12 @@ export const buyQuoteUpdater = {
}
const feePercentage = oc(options.affiliateInfo).feePercentage();
let newBuyQuote: BuyQuote | undefined;
+ const slippagePercentage = SLIPPAGE_PERCENTAGE;
try {
- newBuyQuote = await assetBuyer.getBuyQuoteAsync(asset.assetData, baseUnitValue, { feePercentage });
+ newBuyQuote = await assetBuyer.getBuyQuoteAsync(asset.assetData, baseUnitValue, {
+ feePercentage,
+ slippagePercentage,
+ });
} catch (error) {
const errorMessage = assetUtils.assetBuyerErrorMessage(asset, error);
diff --git a/packages/instant/test/util/asset.test.ts b/packages/instant/test/util/asset.test.ts
index fc4e4e2e4..402a556d5 100644
--- a/packages/instant/test/util/asset.test.ts
+++ b/packages/instant/test/util/asset.test.ts
@@ -1,5 +1,6 @@
-import { AssetBuyerError } from '@0x/asset-buyer';
+import { AssetBuyerError, BigNumber, InsufficientAssetLiquidityError } from '@0x/asset-buyer';
import { AssetProxyId, ObjectMap } from '@0x/types';
+import { Web3Wrapper } from '@0x/web3-wrapper';
import { Asset, AssetMetaData, ERC20Asset, ERC20AssetMetaData, Network, ZeroExInstantError } from '../../src/types';
import { assetUtils } from '../../src/util/asset';
@@ -19,6 +20,16 @@ const ZRX_ASSET: ERC20Asset = {
const META_DATA_MAP: ObjectMap<AssetMetaData> = {
[ZRX_ASSET_DATA]: ZRX_META_DATA,
};
+const WAX_ASSET: ERC20Asset = {
+ assetData: '0xf47261b000000000000000000000000039bb259f66e1c59d5abef88375979b4d20d98022',
+ metaData: {
+ assetProxyId: AssetProxyId.ERC20,
+ decimals: 8,
+ primaryColor: '#EDB740',
+ symbol: 'wax',
+ name: 'WAX',
+ },
+};
describe('assetDataUtil', () => {
describe('bestNameForAsset', () => {
@@ -47,13 +58,39 @@ describe('assetDataUtil', () => {
});
});
describe('assetBuyerErrorMessage', () => {
- it('should return message for InsufficientAssetLiquidity', () => {
+ it('should return message for generic InsufficientAssetLiquidity error', () => {
const insufficientAssetError = new Error(AssetBuyerError.InsufficientAssetLiquidity);
expect(assetUtils.assetBuyerErrorMessage(ZRX_ASSET, insufficientAssetError)).toEqual(
'Not enough ZRX available',
);
});
- it('should return message for InsufficientAssetLiquidity', () => {
+ describe('InsufficientAssetLiquidityError', () => {
+ it('should return custom message for token w/ 18 decimals', () => {
+ const amountAvailable = Web3Wrapper.toBaseUnitAmount(new BigNumber(20.059), 18);
+ expect(
+ assetUtils.assetBuyerErrorMessage(ZRX_ASSET, new InsufficientAssetLiquidityError(amountAvailable)),
+ ).toEqual('There are only 20.05 ZRX available to buy');
+ });
+ it('should return custom message for token w/ 18 decimals and small amount available', () => {
+ const amountAvailable = Web3Wrapper.toBaseUnitAmount(new BigNumber(0.01), 18);
+ expect(
+ assetUtils.assetBuyerErrorMessage(ZRX_ASSET, new InsufficientAssetLiquidityError(amountAvailable)),
+ ).toEqual('There are only 0.01 ZRX available to buy');
+ });
+ it('should return custom message for token w/ 8 decimals', () => {
+ const amountAvailable = Web3Wrapper.toBaseUnitAmount(new BigNumber(3), 8);
+ expect(
+ assetUtils.assetBuyerErrorMessage(WAX_ASSET, new InsufficientAssetLiquidityError(amountAvailable)),
+ ).toEqual('There are only 3 WAX available to buy');
+ });
+ it('should return generic message when amount available rounds to zero', () => {
+ const amountAvailable = Web3Wrapper.toBaseUnitAmount(new BigNumber(0.002), 18);
+ expect(
+ assetUtils.assetBuyerErrorMessage(ZRX_ASSET, new InsufficientAssetLiquidityError(amountAvailable)),
+ ).toEqual('Not enough ZRX available');
+ });
+ });
+ it('should return message for InsufficientZrxLiquidity', () => {
const insufficientZrxError = new Error(AssetBuyerError.InsufficientZrxLiquidity);
expect(assetUtils.assetBuyerErrorMessage(ZRX_ASSET, insufficientZrxError)).toEqual(
'Not enough ZRX available',
diff --git a/packages/monorepo-scripts/src/doc_gen_configs.ts b/packages/monorepo-scripts/src/doc_gen_configs.ts
index 7a14f8664..875590b34 100644
--- a/packages/monorepo-scripts/src/doc_gen_configs.ts
+++ b/packages/monorepo-scripts/src/doc_gen_configs.ts
@@ -9,6 +9,7 @@ export const docGenConfigs: DocGenConfigs = {
Array: 'https://developer.mozilla.org/pt-PT/docs/Web/JavaScript/Reference/Global_Objects/Array',
BigNumber: 'http://mikemcl.github.io/bignumber.js',
Error: 'https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Error',
+ ErrorConstructor: 'https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Error',
Buffer: 'https://github.com/DefinitelyTyped/DefinitelyTyped/blob/master/types/node/v9/index.d.ts#L262',
'solc.StandardContractOutput':
'https://solidity.readthedocs.io/en/v0.4.24/using-the-compiler.html#output-description',