Index: frontend/node_modules/gensync/test/.babelrc
===================================================================
--- frontend/node_modules/gensync/test/.babelrc	(revision 9af201e94b5a79beb92a30858fc54de4bc3b9449)
+++ frontend/node_modules/gensync/test/.babelrc	(revision 9af201e94b5a79beb92a30858fc54de4bc3b9449)
@@ -0,0 +1,5 @@
+{
+  presets: [
+    ["env", { targets: { node: "current" }}],
+  ],
+}
Index: frontend/node_modules/gensync/test/index.test.js
===================================================================
--- frontend/node_modules/gensync/test/index.test.js	(revision 9af201e94b5a79beb92a30858fc54de4bc3b9449)
+++ frontend/node_modules/gensync/test/index.test.js	(revision 9af201e94b5a79beb92a30858fc54de4bc3b9449)
@@ -0,0 +1,489 @@
+"use strict";
+
+const promisify = require("util.promisify");
+const gensync = require("../");
+
+const TEST_ERROR = new Error("TEST_ERROR");
+
+const DID_ERROR = new Error("DID_ERROR");
+
+const doSuccess = gensync({
+  sync: () => 42,
+  async: () => Promise.resolve(42),
+});
+
+const doError = gensync({
+  sync: () => {
+    throw DID_ERROR;
+  },
+  async: () => Promise.reject(DID_ERROR),
+});
+
+function throwTestError() {
+  throw TEST_ERROR;
+}
+
+async function expectResult(
+  fn,
+  arg,
+  { error, value, expectSync = false, syncErrback = expectSync }
+) {
+  if (!expectSync) {
+    expect(() => fn.sync(arg)).toThrow(TEST_ERROR);
+  } else if (error) {
+    expect(() => fn.sync(arg)).toThrow(error);
+  } else {
+    expect(fn.sync(arg)).toBe(value);
+  }
+
+  if (error) {
+    await expect(fn.async(arg)).rejects.toBe(error);
+  } else {
+    await expect(fn.async(arg)).resolves.toBe(value);
+  }
+
+  await new Promise((resolve, reject) => {
+    let sync = true;
+    fn.errback(arg, (err, val) => {
+      try {
+        expect(err).toBe(error);
+        expect(val).toBe(value);
+        expect(sync).toBe(syncErrback);
+
+        resolve();
+      } catch (e) {
+        reject(e);
+      }
+    });
+    sync = false;
+  });
+}
+
+describe("gensync({})", () => {
+  describe("option validation", () => {
+    test("disallow async and errback handler together", () => {
+      try {
+        gensync({
+          sync: throwTestError,
+          async: throwTestError,
+          errback: throwTestError,
+        });
+
+        throwTestError();
+      } catch (err) {
+        expect(err.message).toMatch(
+          /Expected one of either opts.async or opts.errback, but got _both_\./
+        );
+        expect(err.code).toBe("GENSYNC_OPTIONS_ERROR");
+      }
+    });
+
+    test("disallow missing sync handler", () => {
+      try {
+        gensync({
+          async: throwTestError,
+        });
+
+        throwTestError();
+      } catch (err) {
+        expect(err.message).toMatch(/Expected opts.sync to be a function./);
+        expect(err.code).toBe("GENSYNC_OPTIONS_ERROR");
+      }
+    });
+
+    test("errback callback required", () => {
+      const fn = gensync({
+        sync: throwTestError,
+        async: throwTestError,
+      });
+
+      try {
+        fn.errback();
+
+        throwTestError();
+      } catch (err) {
+        expect(err.message).toMatch(/function called without callback/);
+        expect(err.code).toBe("GENSYNC_ERRBACK_NO_CALLBACK");
+      }
+    });
+  });
+
+  describe("generator function metadata", () => {
+    test("automatic naming", () => {
+      expect(
+        gensync({
+          sync: function readFileSync() {},
+          async: () => {},
+        }).name
+      ).toBe("readFile");
+      expect(
+        gensync({
+          sync: function readFile() {},
+          async: () => {},
+        }).name
+      ).toBe("readFile");
+      expect(
+        gensync({
+          sync: function readFileAsync() {},
+          async: () => {},
+        }).name
+      ).toBe("readFileAsync");
+
+      expect(
+        gensync({
+          sync: () => {},
+          async: function readFileSync() {},
+        }).name
+      ).toBe("readFileSync");
+      expect(
+        gensync({
+          sync: () => {},
+          async: function readFile() {},
+        }).name
+      ).toBe("readFile");
+      expect(
+        gensync({
+          sync: () => {},
+          async: function readFileAsync() {},
+        }).name
+      ).toBe("readFile");
+
+      expect(
+        gensync({
+          sync: () => {},
+          errback: function readFileSync() {},
+        }).name
+      ).toBe("readFileSync");
+      expect(
+        gensync({
+          sync: () => {},
+          errback: function readFile() {},
+        }).name
+      ).toBe("readFile");
+      expect(
+        gensync({
+          sync: () => {},
+          errback: function readFileAsync() {},
+        }).name
+      ).toBe("readFileAsync");
+    });
+
+    test("explicit naming", () => {
+      expect(
+        gensync({
+          name: "readFile",
+          sync: () => {},
+          async: () => {},
+        }).name
+      ).toBe("readFile");
+    });
+
+    test("default arity", () => {
+      expect(
+        gensync({
+          sync: function(a, b, c, d, e, f, g) {
+            throwTestError();
+          },
+          async: throwTestError,
+        }).length
+      ).toBe(7);
+    });
+
+    test("explicit arity", () => {
+      expect(
+        gensync({
+          arity: 3,
+          sync: throwTestError,
+          async: throwTestError,
+        }).length
+      ).toBe(3);
+    });
+  });
+
+  describe("'sync' handler", async () => {
+    test("success", async () => {
+      const fn = gensync({
+        sync: (...args) => JSON.stringify(args),
+      });
+
+      await expectResult(fn, 42, { value: "[42]", expectSync: true });
+    });
+
+    test("failure", async () => {
+      const fn = gensync({
+        sync: (...args) => {
+          throw JSON.stringify(args);
+        },
+      });
+
+      await expectResult(fn, 42, { error: "[42]", expectSync: true });
+    });
+  });
+
+  describe("'async' handler", async () => {
+    test("success", async () => {
+      const fn = gensync({
+        sync: throwTestError,
+        async: (...args) => Promise.resolve(JSON.stringify(args)),
+      });
+
+      await expectResult(fn, 42, { value: "[42]" });
+    });
+
+    test("failure", async () => {
+      const fn = gensync({
+        sync: throwTestError,
+        async: (...args) => Promise.reject(JSON.stringify(args)),
+      });
+
+      await expectResult(fn, 42, { error: "[42]" });
+    });
+  });
+
+  describe("'errback' sync handler", async () => {
+    test("success", async () => {
+      const fn = gensync({
+        sync: throwTestError,
+        errback: (...args) => args.pop()(null, JSON.stringify(args)),
+      });
+
+      await expectResult(fn, 42, { value: "[42]", syncErrback: true });
+    });
+
+    test("failure", async () => {
+      const fn = gensync({
+        sync: throwTestError,
+        errback: (...args) => args.pop()(JSON.stringify(args)),
+      });
+
+      await expectResult(fn, 42, { error: "[42]", syncErrback: true });
+    });
+  });
+
+  describe("'errback' async handler", async () => {
+    test("success", async () => {
+      const fn = gensync({
+        sync: throwTestError,
+        errback: (...args) =>
+          process.nextTick(() => args.pop()(null, JSON.stringify(args))),
+      });
+
+      await expectResult(fn, 42, { value: "[42]" });
+    });
+
+    test("failure", async () => {
+      const fn = gensync({
+        sync: throwTestError,
+        errback: (...args) =>
+          process.nextTick(() => args.pop()(JSON.stringify(args))),
+      });
+
+      await expectResult(fn, 42, { error: "[42]" });
+    });
+  });
+});
+
+describe("gensync(function* () {})", () => {
+  test("sync throw before body", async () => {
+    const fn = gensync(function*(arg = throwTestError()) {});
+
+    await expectResult(fn, undefined, {
+      error: TEST_ERROR,
+      syncErrback: true,
+    });
+  });
+
+  test("sync throw inside body", async () => {
+    const fn = gensync(function*() {
+      throwTestError();
+    });
+
+    await expectResult(fn, undefined, {
+      error: TEST_ERROR,
+      syncErrback: true,
+    });
+  });
+
+  test("async throw inside body", async () => {
+    const fn = gensync(function*() {
+      const val = yield* doSuccess();
+      throwTestError();
+    });
+
+    await expectResult(fn, undefined, {
+      error: TEST_ERROR,
+    });
+  });
+
+  test("error inside body", async () => {
+    const fn = gensync(function*() {
+      yield* doError();
+    });
+
+    await expectResult(fn, undefined, {
+      error: DID_ERROR,
+      expectSync: true,
+      syncErrback: false,
+    });
+  });
+
+  test("successful return value", async () => {
+    const fn = gensync(function*() {
+      const value = yield* doSuccess();
+
+      expect(value).toBe(42);
+
+      return 84;
+    });
+
+    await expectResult(fn, undefined, {
+      value: 84,
+      expectSync: true,
+      syncErrback: false,
+    });
+  });
+
+  test("successful final value", async () => {
+    const fn = gensync(function*() {
+      return 42;
+    });
+
+    await expectResult(fn, undefined, {
+      value: 42,
+      expectSync: true,
+    });
+  });
+
+  test("yield unexpected object", async () => {
+    const fn = gensync(function*() {
+      yield {};
+    });
+
+    try {
+      await fn.async();
+
+      throwTestError();
+    } catch (err) {
+      expect(err.message).toMatch(
+        /Got unexpected yielded value in gensync generator/
+      );
+      expect(err.code).toBe("GENSYNC_EXPECTED_START");
+    }
+  });
+
+  test("yield suspend yield", async () => {
+    const fn = gensync(function*() {
+      yield Symbol.for("gensync:v1:start");
+
+      // Should be "yield*" for no error.
+      yield {};
+    });
+
+    try {
+      await fn.async();
+
+      throwTestError();
+    } catch (err) {
+      expect(err.message).toMatch(/Expected GENSYNC_SUSPEND, got {}/);
+      expect(err.code).toBe("GENSYNC_EXPECTED_SUSPEND");
+    }
+  });
+
+  test("yield suspend return", async () => {
+    const fn = gensync(function*() {
+      yield Symbol.for("gensync:v1:start");
+
+      // Should be "yield*" for no error.
+      return {};
+    });
+
+    try {
+      await fn.async();
+
+      throwTestError();
+    } catch (err) {
+      expect(err.message).toMatch(/Unexpected generator completion/);
+      expect(err.code).toBe("GENSYNC_EXPECTED_SUSPEND");
+    }
+  });
+});
+
+describe("gensync.all()", () => {
+  test("success", async () => {
+    const fn = gensync(function*() {
+      const result = yield* gensync.all([doSuccess(), doSuccess()]);
+
+      expect(result).toEqual([42, 42]);
+    });
+
+    await expectResult(fn, undefined, {
+      value: undefined,
+      expectSync: true,
+      syncErrback: false,
+    });
+  });
+
+  test("error first", async () => {
+    const fn = gensync(function*() {
+      yield* gensync.all([doError(), doSuccess()]);
+    });
+
+    await expectResult(fn, undefined, {
+      error: DID_ERROR,
+      expectSync: true,
+      syncErrback: false,
+    });
+  });
+
+  test("error last", async () => {
+    const fn = gensync(function*() {
+      yield* gensync.all([doSuccess(), doError()]);
+    });
+
+    await expectResult(fn, undefined, {
+      error: DID_ERROR,
+      expectSync: true,
+      syncErrback: false,
+    });
+  });
+
+  test("empty list", async () => {
+    const fn = gensync(function*() {
+      yield* gensync.all([]);
+    });
+
+    await expectResult(fn, undefined, {
+      value: undefined,
+      expectSync: true,
+      syncErrback: false,
+    });
+  });
+});
+
+describe("gensync.race()", () => {
+  test("success", async () => {
+    const fn = gensync(function*() {
+      const result = yield* gensync.race([doSuccess(), doError()]);
+
+      expect(result).toEqual(42);
+    });
+
+    await expectResult(fn, undefined, {
+      value: undefined,
+      expectSync: true,
+      syncErrback: false,
+    });
+  });
+
+  test("error", async () => {
+    const fn = gensync(function*() {
+      yield* gensync.race([doError(), doSuccess()]);
+    });
+
+    await expectResult(fn, undefined, {
+      error: DID_ERROR,
+      expectSync: true,
+      syncErrback: false,
+    });
+  });
+});