fix: add json module with jsonStringifyLargeObject

src/lib/json.ts

@@ -0,0 +1,20 @@
+const debug = require('debug')('snyk-json');
+
+/**
+ * Attempt to json-stringify an object which is potentially very large and might exceed the string limit.
+ * If it does exceed the string limit, try again without pretty-print to hopefully come out below the string limit.
+ * @param obj the object from which you want to get a JSON string
+ */
+export function jsonStringifyLargeObject(obj: any): string {
+  let res = '';
+  try {
+    // first try pretty-print
+    res = JSON.stringify(obj, null, 2);
+    return res;
+  } catch (err) {
+    // if that doesn't work, try non-pretty print
+    debug('JSON.stringify failed - trying again without pretty print', err);
+    res = JSON.stringify(obj);
+    return res;
+  }
+}

test/json.spec.ts

@@ -0,0 +1,30 @@
+import { jsonStringifyLargeObject } from '../src/lib/json';
+
+describe('jsonStringifyLargeObject', () => {
+  it('works normally with a small object', () => {
+    const smallObject = {
+      name: 'Brian',
+      isGoodBoy: true,
+    };
+    const s = jsonStringifyLargeObject(smallObject);
+    expect(s).toEqual('{\n  "name": "Brian",\n  "isGoodBoy": true\n}');
+  });
+
+  it('fallsback on non-pretty-print on very large object', () => {
+    const largeObject = {
+      name: 'Brian',
+      isGoodBoy: true,
+      type: 'big',
+    };
+    const jsonStringifyMock = jest
+      .spyOn(JSON, 'stringify')
+      // eslint-disable-next-line @typescript-eslint/no-unused-vars
+      .mockImplementationOnce((any) => {
+        throw new Error('fake error to simulate an `Invalid string length`');
+      });
+
+    const s = jsonStringifyLargeObject(largeObject);
+    expect(jsonStringifyMock).toHaveBeenCalledTimes(2);
+    expect(s).toEqual(`{"name":"Brian","isGoodBoy":true,"type":"big"}`);
+  });
+});