No overload matches this call. Type 'string' is not assignable to type 'Signals'

Question

I am using typescript to build a microservice and handling signals as well. The code was working fine till a few days ago but recently it started throwing errors. Couldn't find a fix for the issue.

code for handling signals. It is just part of the file. src/main.ts

  enum signals {     SIGHUP = 1,     SIGINT = 2,     SIGTERM = 15   }   const shutdown = (signal, value) => {     logger.warn("shutdown!")     Db.closeAll()     process.exit(value)   }   Object.values(signals).forEach(signal => {     process.on(signal, () => {       logger.warn(`process received a ${signal} signal`)       shutdown(signal, signals[signal])     })   }) 

When I do ts-node src/main.ts The following error throws and exits.

 /home/meraj/.nvm/versions/node/v8.10.0/lib/node_modules/ts-node/src/index.ts:245     return new TSError(diagnosticText, diagnosticCodes)            ^ TSError: ⨯ Unable to compile TypeScript: src/main.ts:35:16 - error TS2769: No overload matches this call.   The last overload gave the following error.     Argument of type 'string | signals' is not assignable to parameter of type 'Signals'.       Type 'string' is not assignable to type 'Signals'.  35     process.on(signal, () => {                   ~~~~~~    node_modules/@types/node/base.d.ts:653:9     653         on(event: Signals, listener: SignalsListener): this;                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~     The last overload is declared here.      at createTSError (/home/meraj/.nvm/versions/node/v8.10.0/lib/node_modules/ts-node/src/index.ts:245:12)     at reportTSError (/home/meraj/.nvm/versions/node/v8.10.0/lib/node_modules/ts-node/src/index.ts:249:19)     at getOutput (/home/meraj/.nvm/versions/node/v8.10.0/lib/node_modules/ts-node/src/index.ts:362:34)     at Object.compile (/home/meraj/.nvm/versions/node/v8.10.0/lib/node_modules/ts-node/src/index.ts:395:32)     at Module.m._compile (/home/meraj/.nvm/versions/node/v8.10.0/lib/node_modules/ts-node/src/index.ts:473:43)     at Module._extensions..js (module.js:663:10)     at Object.require.extensions.(anonymous function) [as .ts] (/home/meraj/.nvm/versions/node/v8.10.0/lib/node_modules/ts-node/src/index.ts:476:12)     at Module.load (module.js:565:32)     at tryModuleLoad (module.js:505:12)     at Function.Module._load (module.js:497:3) 

Any fix would be appreciated. Or If you can tell why it was working earlier just 2 days ago and not now.

Answer 1

This sometimes happens when you have passed an incorrect number of arguments to an anonymous function:

    Object.keys(data).reduce((key: string) => {      }, {});  

will raise error:

No overload matches this call. Overload 1 of 3

Pass it the correct number of arguments:

    Object.keys(data).reduce((acc: any, key: string) => {     }, {}); 

Answer 2

I also had this strange issue, but I worked around it using type assertions (in my case using a string enum):

(Object.values(someEnum) as string[]).concat(otherStringArray);