Use json-big

package.json

@@ -33,6 +33,7 @@
   "license": "MIT",
   "dependencies": {
     "axios": "^0.18.0",
+    "json-bigint": "^0.3.0",
     "retry-axios": "0.3.2"
   },
   "devDependencies": {

src/index.ts

@@ -8,6 +8,8 @@
 import axios from 'axios';
 import * as rax from 'retry-axios';
 
+const JSONbig = require('json-bigint');
+
 export const HOST_ADDRESS = 'http://metadata.google.internal';
 export const BASE_PATH = '/computeMetadata/v1';
 export const BASE_URL = HOST_ADDRESS + BASE_PATH;
@@ -52,7 +54,7 @@ async function metadataAccessor<T>(
   }
   validate(options);
   const ax = axios.create({
-    transformResponse: [t => t]  // Do not JSON.parse strings.
+    transformResponse: [t => t]  // Do not use default JSON.parse.
   });
   rax.attach(ax);
   const reqOpts = {
@@ -70,10 +72,9 @@ async function metadataAccessor<T>(
     } else if (!res.data) {
       throw new Error('Invalid response from the metadata service');
     }
-    if (res.headers['content-type'] === 'application/json' &&
-        typeof res.data === 'string') {
+    if (typeof res.data === 'string') {
       try {
-        return JSON.parse(res.data);
+        return JSONbig.parse(res.data);
       } catch {
         /* ignore */
       }

test/index.test.ts

@@ -49,38 +49,36 @@ it('should access a specific metadata property', async () => {
   scope.done();
 });
 
-it('should deal with large numbers', async () => {
+it('should return large numbers as BigNumber values', async () => {
   const BIG_NUMBER_STRING = `3279739563200103600`;
   const scope = nock(HOST)
                     .get(`${PATH}/${TYPE}/${PROPERTY}`)
                     .reply(200, BIG_NUMBER_STRING, HEADERS);
   const property = await gcp.instance(PROPERTY);
-  assert.strictEqual(property, BIG_NUMBER_STRING);
+  // property should be a BigNumber.
+  assert.strictEqual(property.valueOf(), BIG_NUMBER_STRING);
   scope.done();
 });
 
-it('should not JSON.parse text responses', async () => {
-  const RESPONSE = '["Iggety, ziggety, zaggety, ZOOM!", 3279739563200103600]';
-  const headersWithJsonContent =
-      Object.assign({}, HEADERS, {'content-type': 'application/text'});
+it('should return small numbers normally', async () => {
+  const NUMBER = 32797;
   const scope = nock(HOST)
                     .get(`${PATH}/${TYPE}/${PROPERTY}`)
-                    .reply(200, RESPONSE, headersWithJsonContent);
+                    .reply(200, `${NUMBER}`, HEADERS);
   const property = await gcp.instance(PROPERTY);
-  assert.deepStrictEqual(property, RESPONSE);
+  assert.strictEqual(typeof property, 'number');
+  assert.strictEqual(property, NUMBER);
   scope.done();
 });
 
-it('should JSON.parse json responses', async () => {
-  const RESPONSE = '["Iggety, ziggety, zaggety, ZOOM!", 3279739563200103600]';
-  const headersWithJsonContent =
-      Object.assign({}, HEADERS, {'content-type': 'application/json'});
+it('should deal with nested large numbers', async () => {
+  const BIG_NUMBER_STRING = `3279739563200103600`;
+  const RESPONSE = `{ "v1": true, "v2": ${BIG_NUMBER_STRING} }`;
   const scope = nock(HOST)
                     .get(`${PATH}/${TYPE}/${PROPERTY}`)
-                    .reply(200, RESPONSE, headersWithJsonContent);
-  const property = await gcp.instance(PROPERTY);
-  console.log(property);
-  assert.deepStrictEqual(property, JSON.parse(RESPONSE));
+                    .reply(200, RESPONSE, HEADERS);
+  const response = await gcp.instance(PROPERTY);
+  assert.strictEqual(response.v2.valueOf(), BIG_NUMBER_STRING);
   scope.done();
 });