Add initial exchange contract function, set up web3Wrapper, added types and utils

1 files changed, 71 insertions, 0 deletions

diff --git a/src/ts/web3_wrapper.ts b/src/ts/web3_wrapper.ts
new file mode 100644
index 000000000..92781687e
--- /dev/null
+++ b/src/ts/web3_wrapper.ts
@@ -0,0 +1,71 @@
+import * as _ from 'lodash';
+import Web3 from 'web3';
+import * as BigNumber from 'bignumber.js';
+import promisify = require('es6-promisify');
+
+export class Web3Wrapper {
+    private web3: Web3;
+    constructor(web3: Web3) {
+        this.web3 = new Web3();
+        this.web3.setProvider(web3.currentProvider);
+    }
+    public isAddress(address: string): boolean {
+        return this.web3.isAddress(address);
+    }
+    public async getSenderAddressIfExistsAsync(): Promise<string> {
+        const defaultAccount = this.web3.eth.defaultAccount;
+        if (!_.isUndefined(defaultAccount)) {
+            return defaultAccount;
+        }
+        const firstAccount = await this.getFirstAddressIfExistsAsync();
+        return firstAccount;
+    }
+    public async getFirstAddressIfExistsAsync(): Promise<string> {
+        const addresses = await promisify(this.web3.eth.getAccounts)();
+        if (_.isEmpty(addresses)) {
+            return '';
+        }
+        return (addresses as string[])[0];
+    }
+    public async getNodeVersionAsync(): Promise<string> {
+        const nodeVersion = await promisify(this.web3.version.getNode)();
+        return nodeVersion;
+    }
+    public getCurrentProvider(): Web3.Provider {
+        return this.web3.currentProvider;
+    }
+    public async getNetworkIdIfExistsAsync() {
+        try {
+            const networkId = await this.getNetworkAsync();
+            return Number(networkId);
+        } catch (err) {
+            return undefined;
+        }
+    }
+    public async getBalanceInEthAsync(owner: string): Promise<BigNumber.BigNumber> {
+        const balanceInWei = await promisify(this.web3.eth.getBalance)(owner);
+        const balanceEth = this.web3.fromWei(balanceInWei, 'ether');
+        return balanceEth;
+    }
+    public async doesContractExistAtAddressAsync(address: string): Promise<boolean> {
+        const code = await promisify(this.web3.eth.getCode)(address);
+        // Regex matches 0x0, 0x00, 0x in order to accomodate poorly implemented clients
+        const zeroHexAddressRegex = /^0[xX][0]*$/;
+        const didFindCode = _.isNull(code.match(zeroHexAddressRegex));
+        return didFindCode;
+    }
+    // Note: since `sign` is overloaded to be both a sync and async method, it doesn't play nice
+    // with our callAsync method. We therefore handle it here as a special case.
+    public async signTransactionAsync(address: string, message: string): Promise<string> {
+        const signData = await promisify(this.web3.eth.sign)(address, message);
+        return signData;
+    }
+    public async getBlockTimestampAsync(blockHash: string): Promise<number> {
+        const {timestamp} = await promisify(this.web3.eth.getBlock)(blockHash);
+        return timestamp;
+    }
+    private async getNetworkAsync() {
+        const networkId = await promisify(this.web3.version.getNetwork)();
+        return networkId;
+    }
+}