Instantiate client Errors with the correct message.

Fix the issue outlined in #200.

Author: randytarampi

lib/client.js

@@ -145,7 +145,7 @@ export default class Client {
     if (f.length >= 2) {
       if (res && res.body && res.body.type === 'error.list') {
         let message = null;
-        if (Array.isArray(res.body.errors) && res.body.errors[0] && 'message' in res.body.errors) {
+        if (Array.isArray(res.body.errors) && res.body.errors[0] && 'message' in res.body.errors[0]) {
           // Try to use the first errors message
           message = res.body.errors[0].message;
         }

test/errors.js

@@ -45,6 +45,7 @@ describe('errors', () => {
         assert.strictEqual(err.statusCode, 401);
         assert.strictEqual(err.body.request_id, 'b2i3ri5909msvfqskol0');
         assert.deepStrictEqual(err.body.errors, [{ code: 'token_unauthorized', message: 'Not authorized to access resource' }]);
+        assert.deepStrictEqual(err.message, 'Not authorized to access resource');
         assert.strictEqual(err.headers['x-request-id'], 'b2i3ri5909msvfqskol0');
       });
     });
@@ -76,6 +77,7 @@ describe('errors', () => {
         assert.strictEqual(err.statusCode, 429);
         assert.strictEqual(err.body.request_id, 'b2i3mhcboc6pcbe33q80');
         assert.deepStrictEqual(err.body.errors, [{ code: 'rate_limit_exceeded', message: 'Exceeded rate limit of 83 in 10_seconds' }]);
+        assert.deepStrictEqual(err.message, 'Exceeded rate limit of 83 in 10_seconds');
         assert.strictEqual(err.headers['x-request-id'], 'b2i3mhcboc6pcbe33q80');
         assert.strictEqual(err.headers['x-ratelimit-reset'], '1522849880');
       });
@@ -204,6 +206,7 @@ describe('errors', () => {
           assert.strictEqual(err.statusCode, 401);
           assert.strictEqual(err.body.request_id, 'b2i3ri5909msvfqskol0');
           assert.deepStrictEqual(err.body.errors, [{ code: 'token_unauthorized', message: 'Not authorized to access resource' }]);
+          assert.deepStrictEqual(err.message, 'Not authorized to access resource');
           assert.strictEqual(err.headers['x-request-id'], 'b2i3ri5909msvfqskol0');
 
           done();
@@ -237,6 +240,7 @@ describe('errors', () => {
           assert.strictEqual(err.statusCode, 429);
           assert.strictEqual(err.body.request_id, 'b2i3mhcboc6pcbe33q80');
           assert.deepStrictEqual(err.body.errors, [{ code: 'rate_limit_exceeded', message: 'Exceeded rate limit of 83 in 10_seconds' }]);
+          assert.deepStrictEqual(err.message, 'Exceeded rate limit of 83 in 10_seconds');
           assert.strictEqual(err.headers['x-request-id'], 'b2i3mhcboc6pcbe33q80');
           assert.strictEqual(err.headers['x-ratelimit-reset'], '1522849880');