_ref not defined in Create react app. #41

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1. andreoav commented on Jul 24, 2019

   

   andreoav

   on Jul 24, 2019

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   Same issue here with CRA
2. developit commented on Oct 1, 2019

   

   developit

   on Oct 1, 2019

   Last edited by developit

   Owner

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   Hi there - your async function is being transpiled to use helper methods, rather than being an actual async function. If you want to use an async function with Greenlet, you need to tell TypeScript and/or Babel to preserve async functions. In tsconfig.json:

   {
     "compilerOptions": {
       "target": "ES2015"
     }
   }

   For those interested, you can easily check to see what a function "looks like" when it gets compiled by your build system:

   const myFunction = async msg => {
       return msg;
   };
   
   console.log('' + myFunction); 

   If you run the above in a stock CRA setup, you'll notice the compiled code contains a bunch of references to external variables that Greenlet isn't aware of.

   If the tsconfig option doesn't work for folks (perhaps you're still required to support IE11), you can either remove the async/await, or use a String:

   // Option 1: use a non-async function
   const greenletRead = greenlet(msg => {
     // you can optionally use promises here instead of async/await
     return msg;
   })
   
   // Option 2: use a string
   const greenletRead = greenlet(`async function(msg) {
     return msg;
   }`)
   
   await greenletRead('Hey from greenlet');

   ❤️React with ❤️4Reacted by Claudio Holanda Jr., Axel Bocciarelli, Ben Zenker and Mohamad Yusup
3. developit

   added

   questionFurther information is requestedFurther information is requested

   has fix

   on Oct 1, 2019
4. JosephScript commented on Jan 7, 2020

   

   JosephScript

   on Jan 7, 2020

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   I tried option one and am receiving a new error uncaught exception: ReferenceError: promise_default is not defined:

   const greenletRead = greenlet(msg => {
     return new Promise((resolve, reject) => {
       return resolve(msg)
     })
   })

   I'm curious if you have a working example? I need to support IE11.
5. axelboc commented on May 25, 2022

   

   axelboc

   on May 25, 2022

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   It works for me with return Promise.resolve(msg), though I'm using Storybook, not CRA.

   👍React with 👍2Reacted by Henok and Ben Zenker