Ionic-native: Typescript Error Cannot find name 'unknown'.

[kodeine]

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$ ionic serve
> ionic-app-scripts serve --address localhost --port 8100 --livereload-port 35729 --dev-logger-port 53703 --nobrowser
[app-scripts] [16:17:45]  ionic-app-scripts 3.2.4 
[app-scripts] [16:17:45]  watch started ... 
[app-scripts] [16:17:46]  build dev started ... 
[app-scripts] [16:17:46]  clean started ... 
[app-scripts] [16:17:46]  clean finished in 101 ms 
[app-scripts] [16:17:46]  copy started ... 
[app-scripts] [16:17:47]  copy finished in 889 ms 
[app-scripts] [16:17:47]  deeplinks started ... 
[app-scripts] [16:17:50]  deeplinks finished in 2.83 s 
[app-scripts] [16:17:50]  transpile started ... 
[app-scripts] [16:18:06]  typescript: node_modules/@ionic-native/core/decorators/common.d.ts, line: 10 
[app-scripts]             Cannot find name 'unknown'. 
[app-scripts]        L9:  export declare function wrapPromise(pluginObj: any, methodName: string, args: any[], opts?: CordovaOptions): Promise<unknown>;
[app-scripts]       L11:   * Checks if plugin/cordova is available

Ionic Framework: ^3.9.2
Ionic App Scripts: 3.2.4
Angular Core: ^5.2.11
Angular Compiler CLI: ^5.2.11
Node: 11.5.0
OS Platform: macOS High Sierra

[dominikse]

I could fix this issue in first place by replacing Promise<unknown> with Promise<any> in "core/decorators/common.d.ts" file.
I'm pretty sure it is not a proper solution but the error vanished. Still not sure if there will be any side effects...

[mariusbackes]

Which TypeScript version do you use?
In my project I used version 2.6.2 and had the same issue. After upgrading to the latest version (3.6.3) it is working fine.

[dominikse]

Good point!
But in my case upgrading typescript from 2.9.2 to 3.6.4 leads to the following error during ionic serve :-/

[ng] ERROR in The Angular Compiler requires TypeScript >=2.7.2 and <2.10.0 but 3.6.4 was found instead.
[ng] ℹ ｢wdm｣: Failed to compile.

[emanuellandell]

I could fix this issue in first place by replacing Promise<unknown> with Promise<any> in "core/decorators/common.d.ts" file.
I'm pretty sure it is not a proper solution but the error vanished. Still not sure if there will be any side effects...

the only solution I found that worked. Thanks!

[ericgopak]

I could fix this issue in first place by replacing Promise<unknown> with Promise<any> in "core/decorators/common.d.ts" file.
I'm pretty sure it is not a proper solution but the error vanished. Still not sure if there will be any side effects...

Happens to me as well, using typescript 2.6.2 due to angular-cli limitations. The temporary fix by dominikse worked for me

[david-schopf]

Try to add this to a Typescript declaration file of your project:

declare type unknown = any;