loganfsmyth / gensync Goto Github PK

gensync=require('gensync')
as=async()=>new Promise(r=>setTimeout(()=>r(99),1000))
gensync(as).sync()

it trhow error like below, what's wrong?

Uncaught TypeError: gen.next is not a function
at evaluateSync (D:\work\gitee\belt-road\logs\2022-05-23\java-web-2022-05-23-2115\node_modules\gensync\index.js:251:28)
at Function.sync (D:\work\gitee\belt-road\logs\2022-05-23\java-web-2022-05-23-2115\node_modules\gensync\index.js:89:14)

I came across an error about 3 layers abstracted from this repository but a simple configuration change to the deployment would prevent issues with support of newer configurations.

My error occurs within DevExpress/testcafe when evaluating a testcase in es2017 javascript. When a testcase is run, it is transposed via Babel prior to execution. Your package is used by @Babel/core@7. During the babel compilation step, your package processed and it processes your test/index.test.ts which has an unresolved module.

This is the error I get:

$> npm exec -- testcafe chrome:headless **/*.test.js
ERROR Cannot prepare tests due to the following error:

Error: Cannot find module 'util.promisify'
Require stack:
- /<redacted>/eslint-plugin-testcafe-community/example/node_modules/gensync/test/index.test.js
- /<redacted>/eslint-plugin-testcafe-community/example/node_modules/testcafe/lib/compiler/test-file/formats/es-next/compiler.js
- /<redacted>/eslint-plugin-testcafe-community/example/node_modules/testcafe/lib/compiler/compilers.js
- /<redacted>/eslint-plugin-testcafe-community/example/node_modules/testcafe/lib/compiler/index.js
- /<redacted>/eslint-plugin-testcafe-community/example/node_modules/testcafe/lib/runner/bootstrapper.js
- /<redacted>/eslint-plugin-testcafe-community/example/node_modules/testcafe/lib/runner/index.js
- /<redacted>/eslint-plugin-testcafe-community/example/node_modules/testcafe/lib/testcafe.js
- /<redacted>/eslint-plugin-testcafe-community/example/node_modules/testcafe/lib/index.js
- /<redacted>/eslint-plugin-testcafe-community/example/node_modules/testcafe/lib/cli/cli.js
- /<redacted>/eslint-plugin-testcafe-community/example/node_modules/testcafe/lib/cli/index.js

I dug through the code and found this is because of:

// FILE: gensync/test/index.test.js#3
const promisify = require("util.promisify");

This looks like an old implementation of require() that is no longer valid in Node@>=10.24.

I can't figure out why Babel is transpiling the entire module rather than just your package.json[main]. I figure this is an easy fix to just prevent your test code from being included in your package which is likely unintentional.

FYI, New updates in npmv6 & 7 have helped ensure smaller production packages through the use of the files directive.

Reproduction

Create a test.js alongside with index.js

var gensync = require("./index.js");
const isAsync = gensync({ sync: () => false, errback: cb => cb(null, true) });
const gen = (function*() { var async = yield * isAsync(); })();
gen.next();
console.log(gen.next().done);

Run this snippet with node.js 6

node --harmony_tailcalls test.js

Expected
Print true.

Actual

TypeError: Iterator result false is not an object
    at /path/to/gensync/test.js:3:48
    at next (native)
    at Object.<anonymous> (/path/to/gensync/test.js:5:17)

Among the other major implementors, only Safari supports TCO and I could not reproduce this issue on Safari. Therefore it is probably a platform-specific issue and thus, ideally, should be fixed on V8's side.

However Tail Call Optimization has been removed in V8 since node.js 8, so I don't think this issue should be prioritized.

Additional Context
This issue was initially reported at babel/babel#11226.

Cannot find module 'xxx\xxx\node_modules\gensync\index.js'

It is not found in the gensync directory index.js