2020-06-12 10:38:55 +03:00
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_section: Getting Started @<getting-started>
|
2019-08-21 08:53:47 +03:00
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2020-06-12 10:38:55 +03:00
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_subsection: Installing @<installing>
|
2019-08-21 08:53:47 +03:00
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2020-07-07 15:41:23 +03:00
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Ethers' various Classes and Functions are available to import
|
2020-02-02 15:58:29 +03:00
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manually from sub-packages under the [@ethersproject](link-ethers-npm)
|
2020-06-12 10:38:55 +03:00
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organization but for most projects, the umbrella package is the
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easiest way to get started.
|
2019-08-21 08:53:47 +03:00
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2020-04-19 09:18:20 +03:00
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_code: @lang<shell>
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2020-07-07 15:41:23 +03:00
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/home/ricmoo> npm install --save ethers
|
2019-08-21 08:53:47 +03:00
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2020-06-12 10:38:55 +03:00
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_subsection: Importing @<importing>
|
2019-08-21 08:53:47 +03:00
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_heading: Node.js
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2020-05-08 10:24:40 +03:00
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_code: node.js require @lang<script>
|
2020-04-19 09:18:20 +03:00
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const { ethers } = require("ethers");
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2020-05-08 10:24:40 +03:00
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_code: ES6 or TypeScript @lang<script>
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2020-04-19 09:18:20 +03:00
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import { ethers } from "ethers";
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2019-08-21 08:53:47 +03:00
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_heading: Web Browser
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It is generally better practice (for security reasons) to copy the
|
2020-02-02 15:58:29 +03:00
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[ethers library](link-ethers-js) to your own webserver and serve it
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yourself.
|
2019-08-21 08:53:47 +03:00
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|
2020-07-07 15:41:23 +03:00
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For quick demos or prototyping though, you can load it in your
|
2019-08-21 08:53:47 +03:00
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Web Applications from our CDN.
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2020-05-08 10:24:40 +03:00
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_code: ES6 in the Browser @lang<html>
|
2020-04-19 09:18:20 +03:00
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2020-07-05 05:46:47 +03:00
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<script type="module">
|
2021-06-04 08:17:56 +03:00
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import { ethers } from "https://cdn.ethers.io/lib/ethers-5.2.esm.min.js";
|
2020-07-05 05:46:47 +03:00
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// Your code here...
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</script>
|
2020-05-08 10:24:40 +03:00
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_code: ES3 (UMD) in the Browser @lang<html>
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|
2021-06-04 08:17:56 +03:00
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<script src="https://cdn.ethers.io/lib/ethers-5.2.umd.min.js"
|
2020-10-07 00:18:09 +03:00
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type="application/javascript"></script>
|
2020-06-12 10:38:55 +03:00
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_subsection: Common Terminology @<getting-started--glossary>
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This section needs work...
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_table: Common Terms
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$Provider: A Provider (in ethers) is a class which provides an abstraction
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for a connection to the Ethereum Network. It provides read-only
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access to the Blockchain and its status.
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$Signer: A Signer is a class which (usually) in some way directly or
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indirectly has access to a private key, which can sign messages
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and transactions to authorize the network to charge your account
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ether to perform operations.
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$Contract: A Contract is an abstraction which represents a connection to a
|
2020-07-07 15:41:23 +03:00
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specific contract on the Ethereum Network, so that applications
|
2020-10-03 19:30:15 +03:00
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|
can use it like a normal JavaScript object.
|
2020-06-12 10:38:55 +03:00
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| **Provider** | $Provider |
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| **Signer** | $Signer |
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| **Contract** | $Contract |
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_subsection: Connecting to Ethereum: Metamask @<getting-started--connecting>
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The quickest and easiest way to experiment and begin developing on
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Ethereum is to use [[link-metamask]], which is a browser extension
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that provides:
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- A connection to the Ethereum network (a [[Provider]])
|
2020-07-03 08:44:17 +03:00
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|
- Holds your private key and can sign things (a [[Signer]])
|
2020-06-12 10:38:55 +03:00
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_code: Connecting to Metamask @lang<script>
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// A Web3Provider wraps a standard Web3 provider, which is
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|
// what Metamask injects as window.ethereum into each page
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|
const provider = new ethers.providers.Web3Provider(window.ethereum)
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// The Metamask plugin also allows signing transactions to
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// send ether and pay to change state within the blockchain.
|
2020-07-07 15:41:23 +03:00
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|
// For this, you need the account signer...
|
2020-06-12 10:38:55 +03:00
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|
const signer = provider.getSigner()
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|
2020-07-07 15:41:23 +03:00
|
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|
_subsection: Connecting to Ethereum: RPC @<getting-started--connecting-rpc>
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|
The [JSON-RPC API](link-jsonrpc) is another popular method for interacting
|
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|
|
with Ethereum and is available in all major Ethereum node implementations
|
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|
(e.g. [[link-geth]] and [[link-parity]]) as well as many
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|
third-party web services (e.g. [[link-infura]]). It typically provides:
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|
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|
- A connection to the Ethereum network (a [[Provider]])
|
2021-04-02 10:55:06 +03:00
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|
- Holds your private key and can sign things (a [[Signer]])
|
2020-07-07 15:41:23 +03:00
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|
_code: Connecting to an RPC client @lang<script>
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|
// If you don't specify a //url//, Ethers connects to the default
|
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|
// (i.e. ``http:/\/localhost:8545``)
|
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|
const provider = new ethers.providers.JsonRpcProvider();
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|
// The provider also allows signing transactions to
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|
// send ether and pay to change state within the blockchain.
|
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|
|
// For this, we need the account signer...
|
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|
const signer = provider.getSigner()
|
2020-06-12 10:38:55 +03:00
|
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|
_heading: Querying the Blockchain @<getting-started--querying>
|
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|
Once you have a [[Provider]], you have a read-only connection to the
|
2020-07-07 15:41:23 +03:00
|
|
|
blockchain, which you can use to query the current state, fetch historic
|
2020-06-12 10:38:55 +03:00
|
|
|
logs, look up deployed code and so on.
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|
_code: Basic Queries @lang<javascript>
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|
// Look up the current block number
|
2021-06-04 08:17:56 +03:00
|
|
|
//_result:
|
2021-06-11 00:38:38 +03:00
|
|
|
await provider.getBlockNumber()
|
2021-06-04 08:17:56 +03:00
|
|
|
//_log:
|
2020-06-12 10:38:55 +03:00
|
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|
2020-07-07 15:41:23 +03:00
|
|
|
// Get the balance of an account (by address or ENS name, if supported by network)
|
2021-06-04 08:17:56 +03:00
|
|
|
//_result:
|
2020-06-12 10:38:55 +03:00
|
|
|
balance = await provider.getBalance("ethers.eth")
|
2021-06-04 08:17:56 +03:00
|
|
|
//_log:
|
2020-06-12 10:38:55 +03:00
|
|
|
|
2020-07-07 15:41:23 +03:00
|
|
|
// Often you need to format the output to something more user-friendly,
|
|
|
|
|
// such as in ether (instead of wei)
|
2021-06-04 08:17:56 +03:00
|
|
|
//_result:
|
2020-06-12 10:38:55 +03:00
|
|
|
ethers.utils.formatEther(balance)
|
2021-06-04 08:17:56 +03:00
|
|
|
//_log:
|
2020-06-12 10:38:55 +03:00
|
|
|
|
2020-07-07 15:41:23 +03:00
|
|
|
// If a user enters a string in an input field, you may need
|
2020-06-12 10:38:55 +03:00
|
|
|
// to convert it from ether (as a string) to wei (as a BigNumber)
|
2021-06-04 08:17:56 +03:00
|
|
|
//_result:
|
2020-06-12 10:38:55 +03:00
|
|
|
ethers.utils.parseEther("1.0")
|
2021-06-04 08:17:56 +03:00
|
|
|
//_log:
|
2020-06-12 10:38:55 +03:00
|
|
|
|
|
|
|
|
|
|
|
|
|
_heading: Writing to the Blockchain @<getting-started--sending>
|
|
|
|
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|
_code: Sending Ether @lang<script>
|
|
|
|
|
|
|
|
|
|
// Send 1 ether to an ens name.
|
|
|
|
|
const tx = signer.sendTransaction({
|
|
|
|
|
to: "ricmoo.firefly.eth",
|
|
|
|
|
value: ethers.utils.parseEther("1.0")
|
|
|
|
|
});
|
|
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|
_subsection: Contracts @<getting-started--contracts>
|
|
|
|
|
|
|
|
|
|
A Contract is an abstraction of program code which lives on the
|
|
|
|
|
Ethereum blockchain.
|
|
|
|
|
|
|
|
|
|
The [[Contract]] object makes it easier to use an on-chain
|
2020-07-07 15:41:23 +03:00
|
|
|
Contract as a normal JavaScript object, with the methods
|
2020-06-12 10:38:55 +03:00
|
|
|
mapped to encoding and decoding data for you.
|
|
|
|
|
|
2020-09-08 08:11:29 +03:00
|
|
|
If you are familiar with Databases, this is similar to an //Object Relational Mapper// (ORM).
|
2020-06-12 10:38:55 +03:00
|
|
|
|
|
|
|
|
In order to communicate with the Contract on-chain, this class
|
|
|
|
|
needs to know what methods are available and how to encode and
|
2021-02-05 01:21:11 +03:00
|
|
|
decode the data, which is what the //Application Binary Interface// (ABI)
|
2020-06-12 10:38:55 +03:00
|
|
|
provides.
|
|
|
|
|
|
2020-07-14 15:05:55 +03:00
|
|
|
This class is a //meta-class//, which means its methods are constructed
|
|
|
|
|
at runtime, and when you pass in the ABI to the constructor it uses it
|
2020-06-12 10:38:55 +03:00
|
|
|
to determine which methods to add.
|
|
|
|
|
|
2020-07-14 15:05:55 +03:00
|
|
|
While an on-chain Contract may have many methods available, you can safely ignore
|
2020-06-12 10:38:55 +03:00
|
|
|
any methods you don't need or use, providing a smaller subset of the ABI to
|
|
|
|
|
the contract.
|
|
|
|
|
|
2020-07-07 15:41:23 +03:00
|
|
|
An ABI often comes from the Solidity or Vyper compiler, but you can use the
|
|
|
|
|
Human-Readable ABI in code, which the following examples use.
|
2020-06-12 10:38:55 +03:00
|
|
|
|
|
|
|
|
_code: Connecting to the DAI Contract @lang<javascript>
|
|
|
|
|
|
2020-07-07 15:41:23 +03:00
|
|
|
// You can also use an ENS name for the contract address
|
2020-06-12 10:38:55 +03:00
|
|
|
const daiAddress = "dai.tokens.ethers.eth";
|
|
|
|
|
|
|
|
|
|
// The ERC-20 Contract ABI, which is a common contract interface
|
|
|
|
|
// for tokens (this is the Human-Readable ABI format)
|
|
|
|
|
const daiAbi = [
|
2020-07-07 15:41:23 +03:00
|
|
|
// Some details about the token
|
2020-06-12 10:38:55 +03:00
|
|
|
"function name() view returns (string)",
|
|
|
|
|
"function symbol() view returns (string)",
|
|
|
|
|
|
|
|
|
|
// Get the account balance
|
|
|
|
|
"function balanceOf(address) view returns (uint)",
|
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|
|
|
|
|
|
|
|
// Send some of your tokens to someone else
|
|
|
|
|
"function transfer(address to, uint amount)",
|
|
|
|
|
|
|
|
|
|
// An event triggered whenever anyone transfers to someone else
|
|
|
|
|
"event Transfer(address indexed from, address indexed to, uint amount)"
|
|
|
|
|
];
|
|
|
|
|
|
|
|
|
|
// The Contract object
|
|
|
|
|
const daiContract = new ethers.Contract(daiAddress, daiAbi, provider);
|
|
|
|
|
|
2021-06-04 08:17:56 +03:00
|
|
|
//_hide: _page.daiAbi = daiAbi;
|
|
|
|
|
//_hide: _page.daiContract = daiContract;
|
2020-06-12 10:38:55 +03:00
|
|
|
|
|
|
|
|
_heading: Read-Only Methods @<getting-started--reading>
|
|
|
|
|
|
|
|
|
|
_code: Querying the DAI Contract @lang<javascript>
|
|
|
|
|
|
2021-06-04 08:17:56 +03:00
|
|
|
//_hide: const daiContract = _page.daiContract;
|
2020-06-12 10:38:55 +03:00
|
|
|
|
|
|
|
|
// Get the ERC-20 token name
|
2021-06-04 08:17:56 +03:00
|
|
|
//_result:
|
|
|
|
|
await daiContract.name()
|
|
|
|
|
//_log:
|
2020-06-12 10:38:55 +03:00
|
|
|
|
2020-10-03 19:30:15 +03:00
|
|
|
// Get the ERC-20 token symbol (for tickers and UIs)
|
2021-06-04 08:17:56 +03:00
|
|
|
//_result:
|
|
|
|
|
await daiContract.symbol()
|
|
|
|
|
//_log:
|
2020-06-12 10:38:55 +03:00
|
|
|
|
|
|
|
|
// Get the balance of an address
|
|
|
|
|
balance = await daiContract.balanceOf("ricmoo.firefly.eth")
|
2021-06-04 08:17:56 +03:00
|
|
|
//_log: balance
|
2020-06-12 10:38:55 +03:00
|
|
|
|
|
|
|
|
// Format the DAI for displaying to the user
|
2021-06-04 08:17:56 +03:00
|
|
|
//_result:
|
2020-06-12 10:38:55 +03:00
|
|
|
ethers.utils.formatUnits(balance, 18)
|
2021-06-04 08:17:56 +03:00
|
|
|
//_log:
|
2020-06-12 10:38:55 +03:00
|
|
|
|
|
|
|
|
|
|
|
|
|
_heading: State Changing Methods @<getting-started--writing>
|
|
|
|
|
|
|
|
|
|
_code: Sending DAI @lang<script>
|
|
|
|
|
|
|
|
|
|
// The DAI Contract is currently connected to the Provider,
|
2020-07-14 15:05:55 +03:00
|
|
|
// which is read-only. You need to connect to a Signer, so
|
|
|
|
|
// that you can pay to send state-changing transactions.
|
2020-06-12 10:38:55 +03:00
|
|
|
const daiWithSigner = contract.connect(signer);
|
|
|
|
|
|
|
|
|
|
// Each DAI has 18 decimal places
|
|
|
|
|
const dai = ethers.utils.parseUnits("1.0", 18);
|
|
|
|
|
|
|
|
|
|
// Send 1 DAI to "ricmoo.firefly.eth"
|
|
|
|
|
tx = daiWithSigner.transfer("ricmoo.firefly.eth", dai);
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
_heading: Listening to Events @<getting-started--events>
|
|
|
|
|
|
|
|
|
|
_code: Listening to Events @lang<javascript>
|
|
|
|
|
|
2021-06-04 08:17:56 +03:00
|
|
|
//_hide: const daiContract = _page.daiContract;
|
|
|
|
|
//_hide: const formatEther = ethers.utils.formatEther;
|
2020-06-12 10:38:55 +03:00
|
|
|
|
|
|
|
|
// Receive an event when ANY transfer occurs
|
|
|
|
|
daiContract.on("Transfer", (from, to, amount, event) => {
|
|
|
|
|
console.log(`${ from } sent ${ formatEther(amount) } to ${ to}`);
|
|
|
|
|
// The event object contains the verbatim log data, the
|
|
|
|
|
// EventFragment and functions to fetch the block,
|
|
|
|
|
// transaction and receipt and event functions
|
|
|
|
|
});
|
|
|
|
|
|
|
|
|
|
// A filter for when a specific address receives tokens
|
|
|
|
|
myAddress = "0x8ba1f109551bD432803012645Ac136ddd64DBA72";
|
|
|
|
|
filter = daiContract.filters.Transfer(null, myAddress)
|
2021-06-04 08:17:56 +03:00
|
|
|
//_log: filter
|
2020-06-12 10:38:55 +03:00
|
|
|
|
|
|
|
|
// Receive an event when that filter occurs
|
|
|
|
|
daiContract.on(filter, (from, to, amount, event) => {
|
|
|
|
|
// The to will always be "address"
|
|
|
|
|
console.log(`I got ${ formatEther(amount) } from ${ from }.`);
|
|
|
|
|
});
|
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2021-06-04 08:17:56 +03:00
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//_hide: daiContract.removeAllListeners(); /* Don't want to block the docs from compiling... */
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2020-06-12 10:38:55 +03:00
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_heading: Query Historic Events @<getting-started--history>
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_code: Filtering Historic Events @lang<javascript>
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2021-06-04 08:17:56 +03:00
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//_hide: const signer = new ethers.VoidSigner("0x8ba1f109551bD432803012645Ac136ddd64DBA72");
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//_hide: const daiContract = _page.daiContract;
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2020-06-12 10:38:55 +03:00
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// Get the address of the Signer
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myAddress = await signer.getAddress()
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2021-06-04 08:17:56 +03:00
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//_log: myAddress
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2020-06-12 10:38:55 +03:00
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2021-02-05 01:21:11 +03:00
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// Filter for all token transfers from me
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2020-06-12 10:38:55 +03:00
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filterFrom = daiContract.filters.Transfer(myAddress, null);
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2021-06-04 08:17:56 +03:00
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//_log: filterFrom
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2020-06-12 10:38:55 +03:00
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2021-02-05 01:21:11 +03:00
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// Filter for all token transfers to me
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2020-06-12 10:38:55 +03:00
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filterTo = daiContract.filters.Transfer(null, myAddress);
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2021-06-04 08:17:56 +03:00
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//_log: filterTo
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2020-06-12 10:38:55 +03:00
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// List all transfers sent from me a specific block range
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2021-06-04 08:17:56 +03:00
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//_result:
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await daiContract.queryFilter(filterFrom, 9843470, 9843480)
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//_log:
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2020-06-12 10:38:55 +03:00
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//
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// The following have had the results omitted due to the
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// number of entries; but they provide some useful examples
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//
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2020-07-14 15:05:55 +03:00
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// List all transfers sent in the last 10,000 blocks
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2021-06-04 08:17:56 +03:00
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await daiContract.queryFilter(filterFrom, -10000)
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2020-06-12 10:38:55 +03:00
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// List all transfers ever sent to me
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2021-06-04 08:17:56 +03:00
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await daiContract.queryFilter(filterTo)
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2020-06-12 10:38:55 +03:00
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_subsection: Signing Messages @<getting-started--signing>
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_code: Signing Messages @lang<javascript>
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2021-06-04 08:17:56 +03:00
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//_hide: const signer = ethers.Wallet.createRandom();
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2020-06-12 10:38:55 +03:00
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2020-07-14 15:05:55 +03:00
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// To sign a simple string, which are used for
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// logging into a service, such as CryptoKitties,
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2020-06-12 10:38:55 +03:00
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// pass the string in.
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signature = await signer.signMessage("Hello World");
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2021-06-04 08:17:56 +03:00
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//_log: signature
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2020-06-12 10:38:55 +03:00
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//
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// A common case is also signing a hash, which is 32
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// bytes. It is important to note, that to sign binary
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// data it MUST be an Array (or TypedArray)
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//
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2020-07-14 15:05:55 +03:00
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// This string is 66 characters long
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2020-06-12 10:38:55 +03:00
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message = "0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef"
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// This array representation is 32 bytes long
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messageBytes = ethers.utils.arrayify(message);
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2021-06-04 08:17:56 +03:00
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//_log: messageBytes
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2020-06-12 10:38:55 +03:00
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// To sign a hash, you most often want to sign the bytes
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signature = await signer.signMessage(messageBytes)
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2021-06-04 08:17:56 +03:00
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//_log: signature
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