Split 0x.js into contract-wrappers, order-watcher but keep 0x.js as a unifying library with the same interface

packages/contract-wrappers/test/utils/token_utils.ts

@@ -0,0 +1,33 @@
+import * as _ from 'lodash';
+
+import { InternalContractWrappersError, Token } from '../../src/types';
+
+const PROTOCOL_TOKEN_SYMBOL = 'ZRX';
+const WETH_TOKEN_SYMBOL = 'WETH';
+
+export class TokenUtils {
+    private _tokens: Token[];
+    constructor(tokens: Token[]) {
+        this._tokens = tokens;
+    }
+    public getProtocolTokenOrThrow(): Token {
+        const zrxToken = _.find(this._tokens, { symbol: PROTOCOL_TOKEN_SYMBOL });
+        if (_.isUndefined(zrxToken)) {
+            throw new Error(InternalContractWrappersError.ZrxNotInTokenRegistry);
+        }
+        return zrxToken;
+    }
+    public getWethTokenOrThrow(): Token {
+        const wethToken = _.find(this._tokens, { symbol: WETH_TOKEN_SYMBOL });
+        if (_.isUndefined(wethToken)) {
+            throw new Error(InternalContractWrappersError.WethNotInTokenRegistry);
+        }
+        return wethToken;
+    }
+    public getDummyTokens(): Token[] {
+        const dummyTokens = _.filter(this._tokens, token => {
+            return !_.includes([PROTOCOL_TOKEN_SYMBOL, WETH_TOKEN_SYMBOL], token.symbol);
+        });
+        return dummyTokens;
+    }
+}