Cannot find type definition file for 'chai'

[jefbarn]

Edit: fixed in rc4

New in rc.2:

C:\projects\dayapp\node_modules\rxjs\observable\PairsObservable.d.ts
Error:(1, 1) TS2688: Cannot find type definition file for 'chai'.
C:\projects\dayapp\node_modules\rxjs\observable\dom\AjaxObservable.d.ts
Error:(1, 1) TS2688: Cannot find type definition file for 'chai'.

workaround

npm install --save-dev @types/chai

[kwonoj]

Some of transpiled results has unexpected type references,

/// <reference types="chai" />
import { Observable } from '../../Observable';
import { Subscriber } from '../../Subscriber';
import { TeardownLogic } from '../../Subscripti...'

while those file does not uses those type references. Seems it's known issue of TS, updated compiler to latest dev to avoid this.

[Skuriles]

Update to TS 2.1 Dev didn't help. Used 'next' version of TS in package.json.
Gone back to rxjs 5 rc1 and using TS latest (2.0.8) is working so far.
Waiting for fix.

[iamdanfox]

I don't have a solution to this yet, but I think the problem is caused by Typescript's automatic @types detection of node_modules/@types/chai leaking into prod code, caused after switching away from Typings.

1. Local repro

After running npm run build_es6 (with master at 922d04e), I can see four .d.ts files have the problematic line:

/// <reference types="chai" />

2. Minimal example case

src/util/assign.ts is a particularly small source file that ends up with the problematic chai dependency. The problem goes away if we remove any mention of Object from the file - specifically, I changed the signature of assignImpl from:

export function assignImpl(target: Object, ...sources: Object[]) {

to

export function assignImpl(target: any, ...sources: any[]) {

(The three other files also have mentions of Object).

It seems that the @types/chai package that is installed as part of 5.0.0-rc2 mentions Object at line 414:

interface Object {
    should: Chai.Assertion;
}

3. Narrow down the cause

Between 5.0.0-rc.1 and 5.0.0-rc.2, the dist output may have been affected by:

• rxjs switching from using npm install to yarn
• switching from Typings to using the npm @types/ packages. (before, after)

Note, the version of chai never changed from ^3.5.0 and the content of the chai typings file isn't the problem. If I copy typings/globals/chai/index.d.ts from 5.0.0-rc.1 and paste it into node_modules/@types/chai/index.d.ts, I still get four unwanted chai references in the built dist.

I can't see any evidence that yarn is the problem here, it seems much more likely that switching from Typings to the new @types modules caused the problem. Despite having two tsconfig.json files (one for main, one for spec), it seems like the typescript compiler is happily pulling node_modules/@types/chai into main code (when it should only be pulled into spec code).

4. Solutions

Ideally, if we could switch off tsc's node_modules/@types resolution for the main dist, I think this would solve everything. (Not sure if typescript supports this, or is even aware this can be a problem). Alternatively, rxjs could just switch back to using Typings instead of the new npm modules.

I'm sure there are lots of other possible solutions, I defer to the rxjs team to pick a sensible one!

[Skuriles]

JFYI:
I'm actually using some @types (e.g. highcharts , jquery) and this is working with my above mentioned combination (rc1 + TS 2.0.8)

[kwonoj]

@iamdanfox yes, I suspect it's related to microsoft/TypeScript#11948
@Skuriles it'll not be resolved by consumer side TSC version, since type definition is already published includes those references.

I'm seeing couple of options here

• bump up to TS@2.1-dev (fix(Observable): remove unexpected dev dependency type references #2113) : failing tests due to changed behavior
• back to typings
• simply include @types/ as dependency instead of devDependency while waiting compiler issue resolved