312 lines
7.7 KiB
Markdown
312 lines
7.7 KiB
Markdown
# Gas Price Oracle library for Ethereum dApps [](https://github.com/peppersec/gas-price-oracle/actions) [](https://www.npmjs.com/package/gas-price-oracle)
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This is a library with a collection of onchain and offchain gas price oracle URLs
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## Supported networks
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### Ethereum Mainnet
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Current offchain list:
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- https://ethgasstation.info/json/ethgasAPI.json
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- https://etherchain.org/api/gasnow
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Current onchain list:
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- [chainlink](https://etherscan.io/address/0x169e633a2d1e6c10dd91238ba11c4a708dfef37c#readContract)
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### Binance Smart Chain
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Current offchain list:
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- https://ztake.org/
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### Gnosis Chain
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Current offchain list:
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- https://blockscout.com/xdai/mainnet/api/v1/gas-price-oracle
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### Polygon (Matic) Network
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Current offchain list:
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- https://gasstation-mainnet.matic.network/
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### Avalanche C Network
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Current offchain list:
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- https://gavax.blockscan.com/gasapi.ashx?apikey=key&method=gasoracle
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## Installation
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`npm i gas-price-oracle`
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or
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`yarn add gas-price-oracle`
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## Import
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```js
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const { GasPriceOracle } = require('gas-price-oracle')
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or
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import { GasPriceOracle } from 'gas-price-oracle'
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```
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## Usage
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### Configuration
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```typescript
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type GasPrice = Record<'instant' | 'fast' | 'standard' | 'low', number>
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type EstimatedGasPrice = {
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maxFeePerGas: number
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baseFee: number | undefined
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maxPriorityFeePerGas: number
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}
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type FallbackGasPrices = {
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gasPrices?: GasPrice
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estimated?: EstimatedGasPrice
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}
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type GasOracleOptions = {
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chainId?: number
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timeout?: number
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defaultRpc?: string
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blocksCount?: number
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percentile?: number
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blockTime?: number // seconds
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shouldCache?: boolean
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fallbackGasPrices?: FallbackGasPrices
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}
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const options: GasOracleOptions = {
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chainId: 1,
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percentile: 5, // Which percentile of effective priority fees to include
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blocksCount: 10, // How many blocks to consider for priority fee estimation
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defaultRpc: 'https://api.mycryptoapi.com/eth',
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blockTime: 10, // seconds
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shouldCache: false,
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timeout: 10000, // specifies the number of milliseconds before the request times out.
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minPriority: 0, // specifies the min maxPriorityFeePerGas.
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fallbackGasPrices: {
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gasPrices: {
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instant: 28,
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fast: 22,
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standard: 17,
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low: 11,
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},
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estimated: {
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maxFeePerGas: 20,
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maxPriorityFeePerGas: 3,
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},
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},
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}
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```
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### The Oracle can cache rpc calls
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For caching needs to provide to GasOracleOptions
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`shouldCache: true`
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`blockTime: <Chain block time duration>`
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### EIP-1559 (estimated) gasPrice only
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```typescript
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const oracle = new GasPriceOracle({ chainId: 1 })
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type EstimatedGasPrice = {
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maxFeePerGas: number
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baseFee: number | undefined
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maxPriorityFeePerGas: number
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}
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fallbackGasPrices: EstimatedGasPrice = {
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maxFeePerGas: 20,
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maxPriorityFeePerGas: 3,
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}
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oracle.eip1559.estimateFees(fallbackGasPrices).then((gasPrices: EstimatedGasPrice) => {
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console.log(gasPrices) // { baseFee: 14, maxFeePerGas: 17, maxPriorityFeePerGas: 3 }
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})
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```
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### Legacy gasPrice only
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```typescript
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const oracle = new GasPriceOracle({ chainId: 1 })
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type GasPrice = Record<'instant' | 'fast' | 'standard' | 'low', number>
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fallbackGasPrices: GasPrice = {
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instant: 28,
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fast: 22,
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standard: 17,
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low: 11,
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}
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oracle.legacy.gasPrices(fallbackGasPrices).then((gasPrices: GasPrice) => {
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console.log(gasPrices) // { instant: 21.5, fast: 19, standard: 17, low: 15 }
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})
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```
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The `oracle.legacy.gasPrices` method also accepts `shouldGetMedian` argument (`true`) by default. For more details see [below](#offchain-oracles-only-get-median-price).
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Under the hood it's a combination of `fetchMedianGasPriceOffChain`(`fetchGasPricesOffChain`) and `fetchGasPricesOnChain` methods.
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### Estimated gasPrices (EIP-1559) and Legacy gasPrice
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```ts
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const oracle = new GasPriceOracle(options)
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type GasPriceWithEstimate = {
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gasPrices: GasPrice
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estimate: EstimatedGasPrice
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}
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type GasPricesWithEstimateInput = {
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shouldGetMedian?: boolean
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fallbackGasPrices?: FallbackGasPrices
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}
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// optional fallbackGasPrices
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const fallbackGasPrices: FallbackGasPrices = {
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gasPrices: {
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instant: 28,
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fast: 22,
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standard: 17,
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low: 11,
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},
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estimated: {
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maxFeePerGas: 20,
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maxPriorityFeePerGas: 3,
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},
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}
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oracle.gasPricesWithEstimate({ fallbackGasPrices, shouldGetMedian: true }).then((gasPrices: GasPriceWithEstimate) => {
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console.log(gasPrices) // {
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// estimated: { baseFee: 14, maxFeePerGas: 17, maxPriorityFeePerGas: 3 },
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// gasPrices: { instant: 21.5, fast: 19, standard: 17, low: 15 }
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// }}
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})
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```
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### Estimated gasPrices (EIP-1559) or Legacy gasPrice
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```typescript
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const oracle = new GasPriceOracle(options)
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type GetGasPriceInput = {
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isLegacy?: boolean
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shouldGetMedian?: boolean
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fallbackGasPrices?: GasPrice
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}
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// optional fallbackGasPrices
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const fallbackGasPrices: FallbackGasPrices = {
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gasPrices: {
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instant: 28,
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fast: 22,
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standard: 17,
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low: 11,
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},
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estimated: {
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maxFeePerGas: 20,
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maxPriorityFeePerGas: 3,
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},
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}
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oracle.gasPrices({ fallbackGasPrices, shouldGetMedian: true }).then((gasPrices: GasPrice | EstimatedGasPrice) => {
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console.log(gasPrices) // {
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// baseFee: 14, maxFeePerGas: 17, maxPriorityFeePerGas: 3 ||
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// instant: 21.5, fast: 19, standard: 17, low: 15
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// }}
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})
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```
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The `gasPrices` method also accepts `isLegacy` argument (`false`) by default. If `isLegacy: true` - `legacy gasPrice` will be provided. If the `estimate Gas` crashes, `legacy gas Price` will be provided.
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### Get transaction gasPrice params
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```typescript
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const oracle = new GasPriceOracle(options)
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type GetTxGasParamsInput = {
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bumpPercent?: number
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legacySpeed?: GasPriceKey
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isLegacy?: boolean
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shouldGetMedian?: boolean
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fallbackGasPrices?: FallbackGasPrices
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}
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type GetTxGasParamsRes =
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gasPrice: number
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}
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maxFeePerGas: number
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maxPriorityFeePerGas: number
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}
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const gasParams: GetTxGasParamsRes = await oracle.getTxGasParams({ legacySpeed: 'fast', bumpPercent: 30 })
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console.log(gasParams) // { maxFeePerGas: 17, maxPriorityFeePerGas: 3 } || { gasPrice: 19 }
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web3.eth.sendTransaction({
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from: '0xEA674fdDe714fd979de3EdF0F56AA9716B898ec8',
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to: '0xac03bb73b6a9e108530aff4df5077c2b3d481e5a',
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nonce: '0',
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gasLimit: '21000',
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value: '10000000000',
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...gasParams,
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})
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```
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`bumpPercent` argument (`0` by default) - response data will increase by `bumpPercent`%.
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`legacySpeed` argument (`fast` by default) - select the speed of legacy gasPrice.
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### Offchain oracles only
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```typescript
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const oracle = new GasPriceOracle({ chainId: 1 })
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// shouldGetMedian: boolean | undefined
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oracle.legacy.fetchGasPricesOffChain((shouldGetMedian = true)).then((gasPrices: GasPrice) => {
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console.log(gasPrices) // { instant: 50, fast: 21, standard: 10, low: 3 }
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})
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```
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### Offchain oracles only (get median price)
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```typescript
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const oracle = new GasPriceOracle({ chainId: 1 })
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oracle.legacy.fetchMedianGasPriceOffChain().then((gasPrices: GasPrice) => {
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console.log(gasPrices) // { instant: 50, fast: 21, standard: 10, low: 3 }
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})
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```
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This command provides the median gas price of all configured oracles.
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### Custom RPC URL for onchain oracles
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```typescript
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const defaultRpc = 'https://mainnet.infura.io/v3/<API_KEY>'
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const oracle = new GasPriceOracle({ defaultRpc, chainId: 1 })
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oracle.legacy.fetchGasPricesOnChain().then((gasPrices: number) => {
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console.log(gasPrices) // 21
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})
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```
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To get gasPrices from a chain outside of the application's chain list (Binance, Gnosis, Polygon, Avalanche), you should enter the rpcUrl into initial GasPriceOracle options\_
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```typescript
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const defaultRpc = 'https://rpc.goerli.mudit.blog/' // goerli public rpcUrl
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const oracle = new GasPriceOracle({ defaultRpc, chainId: 5 })
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oracle.gasPrices()
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```
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