Remove ethereum-address dependency and add this logic to the repo

3 files changed, 39 insertions, 4 deletions

diff --git a/packages/assert/package.json b/packages/assert/package.json
index 65b163c21..800207ae6 100644
--- a/packages/assert/package.json
+++ b/packages/assert/package.json
@@ -39,7 +39,7 @@
   "dependencies": {
     "@0xproject/json-schemas": "^0.6.10",
     "bignumber.js": "~4.1.0",
-    "ethereum-address": "^0.0.4",
+    "js-sha3": "^0.7.0",
     "lodash": "^4.17.4",
     "valid-url": "^1.0.9"
   }
diff --git a/packages/assert/src/address_utils.ts b/packages/assert/src/address_utils.ts
new file mode 100644
index 000000000..bdbcd3a89
--- /dev/null
+++ b/packages/assert/src/address_utils.ts
@@ -0,0 +1,34 @@
+import * as jsSHA3 from 'js-sha3';
+
+const BASIC_ADDRESS_REGEX = /^(0x)?[0-9a-f]{40}$/i;
+const SAME_CASE_ADDRESS_REGEX = /^(0x)?([0-9a-f]{40}|[0-9A-F]{40})$/;
+
+export const addressUtils = {
+    isChecksumAddress(address: string): boolean {
+        // Check each case
+        const unprefixedAddress = address.replace('0x', '');
+        const addressHash = jsSHA3.keccak256(unprefixedAddress.toLowerCase());
+
+        for (let i = 0; i < 40; i++) {
+            // The nth letter should be uppercase if the nth digit of casemap is 1
+            if ((parseInt(addressHash[i], 16) > 7 && unprefixedAddress[i].toUpperCase() !== unprefixedAddress[i]) ||
+                (parseInt(addressHash[i], 16) <= 7 && unprefixedAddress[i].toLowerCase() !== unprefixedAddress[i])) {
+                return false;
+            }
+        }
+        return true;
+    },
+    isAddress(address: string): boolean {
+        if (!BASIC_ADDRESS_REGEX.test(address)) {
+            // Check if it has the basic requirements of an address
+            return false;
+        } else if (SAME_CASE_ADDRESS_REGEX.test(address)) {
+            // If it's all small caps or all all caps, return true
+            return true;
+        } else {
+            // Otherwise check each case
+            const isValidChecksummedAddress = addressUtils.isChecksumAddress(address);
+            return isValidChecksummedAddress;
+        }
+    },
+};
diff --git a/packages/assert/src/index.ts b/packages/assert/src/index.ts
index 92bcf6f03..94900074a 100644
--- a/packages/assert/src/index.ts
+++ b/packages/assert/src/index.ts
@@ -3,10 +3,11 @@ import {
     SchemaValidator,
 } from '@0xproject/json-schemas';
 import BigNumber from 'bignumber.js';
-import * as ethereum_address from 'ethereum-address';
 import * as _ from 'lodash';
 import * as validUrl from 'valid-url';
 
+import {addressUtils} from './address_utils';
+
 const HEX_REGEX = /^0x[0-9A-F]*$/i;
 
 export const assert = {
@@ -35,9 +36,9 @@ export const assert = {
             this.typeAssertionMessage(variableName, 'HexString', value));
     },
     isETHAddressHex(variableName: string, value: string): void {
-        this.assert(ethereum_address.isAddress(value), this.typeAssertionMessage(variableName, 'ETHAddressHex', value));
+        this.assert(addressUtils.isAddress(value), this.typeAssertionMessage(variableName, 'ETHAddressHex', value));
         this.assert(
-            ethereum_address.isAddress(value) && value.toLowerCase() === value,
+            addressUtils.isAddress(value) && value.toLowerCase() === value,
             `Checksummed addresses are not supported. Convert ${variableName} to lower case before passing`,
         );
     },