flex-ether-fix

A modern, flexible Ethereum library for sending ethereum transactions that:

• Requires minimal to no configuration to get going on all networks (no provider necessary).
• Can sign and send transactions from arbitrary wallets (private keys).
• Provides separate promises for transaction hashes, receipts, and confirmations.
• Automatically calculates gas and gas price for transactions in a configurable manner.
• Automatically resolves ENS addresses across all inputs.

Installation

npm install flex-ether-fix
# or
yarn install flex-ether-fix

Preview Send 1 Ether with Rinkeby Network

//app.js
const FlexEther = require('flex-ether-fix');
//change rinkeby to main for mainnet
const eth = new FlexEther({
    network: 'rinkeby',
    infuraKey: 'd3d4f49d8c284642b36eeef8834a421e',
    providerURI: 'https://rinkeby.infura.io/v3/d3d4f49d8c284642b36eeef8834a421e',
});

async function GetBalance(addr, cb){
    cb(await eth.getBalance(addr))
}

async function SendEther(PrivateKey,ReceiverAddress,amount,cb){
    try {
        cb(await eth.transfer(ReceiverAddress, amount,{key: PrivateKey}))
    } catch(err) {
        console.log(err)
    }
}

GetBalance('0x01F8505B9B33e88c339E02C7338F7d95DDeb1b48',(res)=>{
    console.log(res)
})
SendEther('2563D39BBCF84ED34132DE0E044841CD130F7A872E1785D82503772DF0B8143D','0x3b066c7967c36068aee603D956FE82B1b7af2Db1',1,(res)=>{
    console.log(res)
})

User Guide

• Creating an instance
• Sending ether
• Transaction promises
• Getting balances
• Estimating gas
• ENS addresses
• Instance Properties

Creating an instance

By default, the instance will create an Infura provider to talk to the main network. You can modify this behavior with the options network, infuraKey, provider, or providerURI.

Full options

eth = new FlexEther(
   // Options object. May be omitted.
   {
      // Network to use with Infura provider.
      // May be 'main', 'ropsten', 'rinkeby', or 'kovan'.
      // Defaults to 'main'
      network: String,
      // Infura Project ID, if not using a custom provider.
      infuraKey: String,
      // Connect to an existing provider at a URI
      // (e.g., http://localhost:8545 or https://mainnet.infura.io/v3/PROJECT_ID).
      // The 'net' option is required is using an IPC path.
      providerURI: String,
      // net instance, from require('net'), if using IPC path in providerURI
      net: Object,
      // Use a custom provider instance (e.g., web3.currentProvider for metamask).
      provider: Object,
      // Clamp transaction gas prices to this amount (in wei).
      // Defaults to 250 gwei.
      maxGasPrice: string,
      // Fractional bonus to apply to gas price when making transactions.
      // 0.01 = +1%. May be negative to under-price.
      // Defaults to -0.005.
      // Can be overridden in send/transfer calls.
      gasPriceBonus: Number,
      // Fractional bonus to apply to gas limit estimates when making transactions.
      // 0.01 = +1%. May be negative, but probably not a good idea.
      // Defaults to 0.66.
      // Can be overridden in send/transfer calls.
      gasBonus: Number,
      // ENS options.
      ens: {
          // Minimum number of seconds time to keep a resolved ENS name in cache.
          // Defaults to one hour.
          minTTL: Number,
          // Maximum number of seconds time to keep a resolved ENS name in cache.
          // Defaults to infinity.
          maxTTL: Number,
      }
   });

Sending ether

Ether can be sent with the transfer() or the lower-level send() methods.

By default, transactions will be signed by the wallet associated with the first account given by the provider. You can override the caller by either passing the from or key option. The from option will let the provider sign the transaction from an unlocked wallet, as usual. But, the key option will self-sign the transaction with the private key provided, allowing you to transact from any wallet you have the private keys to.

Transactions return a Transaction Promise Object, which allow you to easily wait on transaction hashes, receipts, and confirmations.

Examples

const FlexEther = require('flex-ether-fix');
// A self-signing wallet key for transactions.
const PRIVATE_KEY = '0xb3734ec890893585330c71ece72afb05058192b6be47bee2b99714e6bb5696ab';
const eth = new FlexEther();

// Send 1 ether to an ENS address and wait for the receipt.
let receipt = await eth.transfer('ethereum.eth', 1);
/* Result: <Receipt Object> {
   transactionHash: '0x9eb3f89f8581e6c6df294344b538d44e265c226ae6e8ce6210df497cf2b54bd3',
   blockNumber: 3616104,
   gasUsed: 21000,
   ... etc.
}*/
// Send 1 ether to an address and wait for the transaction hash.
let txId = await eth.transfer(
   '0xf6fb5b73987d6d9a139e23bab97be6fc89e0dcd1', 1).txId;
// Send 1 ether to an address and wait for the receipt after 3 confirmations.
receipt = await eth.transfer(
   '0xf6fb5b73987d6d9a139e23bab97be6fc89e0dcd1', 1).confirmed(3);
// Send 1 ether from a wallet managed by the provider and wait for the receipt
receipt = await eth.transfer(
   '0xf6fb5b73987d6d9a139e23bab97be6fc89e0dcd1', 1,
   {from: '0x005B68A967D39c497074127871297b6728a1cfEd'});
// Send 1 ether from a wallet defined by a private key and wait for the receipt
receipt = await eth.transfer(
   '0xf6fb5b73987d6d9a139e23bab97be6fc89e0dcd1', 1, {key: PRIVATE_KEY});
// Same as above but with send().
receipt = await eth.send(
   '0xf6fb5b73987d6d9a139e23bab97be6fc89e0dcd1', {value: 1, key: PRIVATE_KEY});

Full options

// Full method options.
await eth.transfer(
   // Recipient address. May be an ENS address.
   to: String,
   // Amount of ether to send, in weis.
   // Can be a base-10 string or hex-encoded number.
   amount: String,
   // Options.
   {
      // Address of wallet that will sign the transaction. May be an ENS address.
      // Must be unlocked by the provider.
      // Defaults to eth.getDefaultAccount().
      from: String,
      // Hex-encoded string private key.
      // Signs the transaction with this private key and sends it from the address
      // associated with it. Overrides 'from' option.
      key: String,
      // Gas price to use, as a hex or base-10 string, in wei.
      // If not specified, calculated from network gas price and bonus.
      gasPrice: String,
      // Execution gas limit.
      // If not specified, it will be estimated with bonus.
      gas: Number,
      // Bonus to apply to gas price calculations.
      // Should be a positive or negative Number, where 0.01 = +1%.
      // If omitted, `eth.gasPriceBonus` will be used.
      gasPriceBonus: undefined,
      // Bonus to apply to gas limit calculations.
      // Should be a positive or negative Number, where 0.01 = +1%.
      // If omitted, `eth.gasBonus` will be used.
      gasBonus: undefined
   });

Transaction promises

transfer() and send() both return a Promise object that resolves to the transaction receipt, once the transaction has been mined.

This Promise object also has the following properties:

• txId: a promise that resolves to the transaction hash when the transaction is posted to the blockchain. This ususally comes much sooner than the receipt.
• receipt: a promise that resolves to the transaction receipt when the transaction has been mined. Same as waiting on the parent object itself.
• confirmed(count=1) a function that returns a promise that resolves to the transaction receipt after the transaction has been mined and count number of confirmations have been seen, up to a maximum of 12 confirmations.

Example

const FlexEther = require('flex-ether-fix');
const eth = new FlexEther();

// Send 1 ether to an address and wait for the receipt.
let receipt = await eth.transfer(
   '0xf6fb5b73987d6d9a139e23bab97be6fc89e0dcd1', 1);
// Send 1 ether to an address and get the promise object.
let tx = eth.transfer(
   '0xf6fb5b73987d6d9a139e23bab97be6fc89e0dcd1', 1);
// Wait on the transaction hash.
let transactionHash = await tx.txId;
// Wait on the receipt. Equivalent to `await tx`
receipt = await tx.receipt;
// Wait on the receipt after 3 confirmations. Equivalent to `await tx`
receipt = await tx.confirmed(3);

Getting balances

The getBalance() method queries the balance of an address.

You can also pass the block number at which to evaluate the balance. These numbers can either be explicit block numbers or negative offsets from the last block number, where -1 is the last block, -2 is the second to last block, and so on.

Examples

const FlexEther = require('flex-ether-fix');
const eth = new FlexEther();

// Get the balance of an address at the current block.
let bal = await eth.getBalance('0xf6fb5b73987d6d9a139e23bab97be6fc89e0dcd1');
// Get the balance of an address at a specific block.
bal = await eth.getBalance('0xf6fb5b73987d6d9a139e23bab97be6fc89e0dcd1', 310319);
// Get the balance of an ENS address at the second to last block.
bal = await eth.getBalance('ethereum.eth', -2);

Estimating gas

Sending ether from wallet to wallet generally costs exactly 21000 gas. However, sending ether to a contract may actually cost more, as it might trigger the execution of code. By default, the library will automatically compute and allocate the gas needed before sending a transaction.

You can get the gas explicitly by calling estimateGas() with the same parameters you would pass to send().

Examples

const FlexEther = require('flex-ether-fix');
// A self-signing wallet key for transactions.
const PRIVATE_KEY = '0xb3734ec890893585330c71ece72afb05058192b6be47bee2b99714e6bb5696ab';
const eth = new FlexEther();

// Get the gas consumed by sending 1 ether to an address from the default account.
let gas = await eth.estimateGas('0xf6fb5b73987d6d9a139e23bab97be6fc89e0dcd1',
   {value: 1});
// Get the gas consumed by sending 1 ether to an address from a wallet defined by
// a private key.
let gas = await eth.estimateGas('0xf6fb5b73987d6d9a139e23bab97be6fc89e0dcd1',
   {value: 1, key: PRIVATE_KEY});

ENS addresses

Anywhere you can pass an address, you can instead pass an ENS address, such as 'thisismyensaddress.eth'. You can also call the resolveAddress() method to resolve an address explicitly. If an ENS address cannot be resolved, an exception will be raised (the promise will fail).

ENS is only available on the main, ropsten, and rinkeby networks. The ENS address will also have to be set up with the ENS contract on the respective network to properly resolve.

Instance Properties

A contract instance exposes a few properties, most of which you are free to change. Many of these can also be overridden in individual call options.

• gasBonus (Number) Gas limit estimate bonus for transactions, where 0.01 = +1%. May be negative.
• gasPriceBonus (Number) Gas price bonus for transactions, where 0.01 = +1%. May be negative.
• async getTransactionCount(addr) Get the nonce for an account.
• async resolveBlockDirective(blockNum) Resolve a block directive (e.g., 41204102 or -2) to a block number.
• async getChainId() Get the chain ID of the connected network.
• async resolveAddress(addr) Resolve an ENS address. If a regular address is passed, the checksummed version will be returned.
• async getBlockNumber() Get the current block number.
• async getDefaultAccount() Get the default account, set by the provider.

Module Properties

The following module properties affect gas calculations for all instances:

• MAX_GAS_PRICE Maximum gas price for transactions. Defaults to 256 gwei.