The Promise type is now incomplete without the property

Question

The Promise type is now incomplete without the property

I'm confident I can resolve this issue on my own, but if sharing my solution can save someone else time, then I want to do so.

To address the error, I needed to incorporate the es6-promise library.

The problem arose when utilizing Promise.all and encountering an issue regarding types. More details in <a href="https://stackoverflow.com/questions/43119163/typescript-error-ts2693-promise-only-refers-to-a-type-but-is-being-used-as#43122423">this discussion</a>.

Initially everything was functioning correctly, however, now I am facing an error specifically when working with a Promise from MongoDB.

Encountering an error stating: "Promise<whatever> is not assignable to Promise<any>. Property 'finally' is missing in type Promise<whatever>"

It seems that there may be compatibility issues related to the addition of a finally property on the Promise return from Mongo. This discrepancy does not exist in the version acquired from es6-promise, detailed in this es6-promise issue.

Any suggestions or solutions?

typescript es6-promise finally

Answer 1

Answer №1

I was the one who initially pointed out that the finally shim was causing compatibility issues with Promises on the mentioned linked thread. It's great to see this problem getting some attention. Here are a couple of solutions:

1. Stick to TypeScript core library typings only

tsconfig.json

{
    "compilerOptions": {
        "lib": ["DOM","ES5","ScriptHost", "es2018.promise"]
    }
}

You can install the shim, execute the polyfill once at the beginning of your application, and then use the global Promise object instead of importing the Promise class from es6-promise. This method has proven to be the most compatible.

npm install --save es6-promise@latest

Please note that recent versions of es6-promise have been including conflicting typings that clash with TypeScript's built-in Promise libraries.

2. Go back to an earlier version of `es6-promise` without the `finally` shim

Keep in mind: This means you won't have access to finally

{
    "compilerOptions": {
        "lib": ["DOM","ES5","ScriptHost"]
    }
}

Install the previous version of es6-promise before they introduced finally, and use those typings:

npm install --save <a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="046177322974766b696d776144302a362a36">[email protected]</a> && npm install --save-dev @types/<a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="d3b6a0e5fea3a1bcbebaa0b693e3fde3fde0e1">[email protected]</a>

(Alternatively, you could skip those typings and add es2015.promise to your compilerOptions.lib array in tsconfig.json.)

Answer 2

I was the one who initially pointed out that the finally shim was causing compatibility issues with Promises on the mentioned linked thread. It's great to see this problem getting some attention. Here are a couple of solutions:

1. Stick to TypeScript core library typings only

tsconfig.json

{
    "compilerOptions": {
        "lib": ["DOM","ES5","ScriptHost", "es2018.promise"]
    }
}

You can install the shim, execute the polyfill once at the beginning of your application, and then use the global Promise object instead of importing the Promise class from es6-promise. This method has proven to be the most compatible.

npm install --save es6-promise@latest

Please note that recent versions of es6-promise have been including conflicting typings that clash with TypeScript's built-in Promise libraries.

2. Go back to an earlier version of `es6-promise` without the `finally` shim

Keep in mind: This means you won't have access to finally

{
    "compilerOptions": {
        "lib": ["DOM","ES5","ScriptHost"]
    }
}

Install the previous version of es6-promise before they introduced finally, and use those typings:

npm install --save <a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="046177322974766b696d776144302a362a36">[email protected]</a> && npm install --save-dev @types/<a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="d3b6a0e5fea3a1bcbebaa0b693e3fde3fde0e1">[email protected]</a>

(Alternatively, you could skip those typings and add es2015.promise to your compilerOptions.lib array in tsconfig.json.)

Answer 3

Answer №2

If you are in need of an accurate type definition for a Promise, it is recommended to utilize the pre-existing definitions that are included with typescript. This suggestion is based on your mention of using a promise with the expected finally method.

To achieve this, simply eliminate es6-promise from your project and modify the lib in your tsconfig as follows:

{
    ....
    "lib": ["es5","es2015.promise","dom", "scripthost"] 
    ....
}

Answer 4

If you are in need of an accurate type definition for a Promise, it is recommended to utilize the pre-existing definitions that are included with typescript. This suggestion is based on your mention of using a promise with the expected finally method.

To achieve this, simply eliminate es6-promise from your project and modify the lib in your tsconfig as follows:

{
    ....
    "lib": ["es5","es2015.promise","dom", "scripthost"] 
    ....
}

The Promise type is now incomplete without the property

Answer №1

1. Stick to TypeScript core library typings only

2. Go back to an earlier version of `es6-promise` without the `finally` shim

Answer №2

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The Promise type is now incomplete without the property

Answer №1

1. Stick to TypeScript core library typings only

2. Go back to an earlier version of es6-promise without the finally shim

Answer №2

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2. Go back to an earlier version of `es6-promise` without the `finally` shim