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Different TS-JEST / TS emitted code when importing 3rd party libs

See original GitHub issue

Continuing the discussion from issue 209

For the same code compiled with TS, ts-jest emits a different output.

Both tsconfig file are identical (one for regular TS compilation, one for ts-jest)
allowSyntheticDefaultImports set to true.

When using this statement:

import * as pathToRegexp from 'path-to-regexp';

In TS compilation without ts-jest pathToRegexp is a function In TS compilation with ts-jest pathToRegexp is an object.

It’s not deterministic, different outcome for the same TS compilation process

Issue Analytics

State:
Created 6 years ago
Comments:20 (9 by maintainers)

Top GitHub Comments

1reaction

kulshekharcommented, May 17, 2017

Another thing going for option 2 is that it makes sure the users know what’s going on.

Currently, as you pointed out as well, users have no idea that ts-jest uses babel when allowSyntheticDefaultImports is set to true. It’s also not very intuitive. If I came across something like this in another library, I’d be at my wits end should something related go wrong and I have to debug it!

It is a breaking change but the fix required at the users’ end would be straightforward - set transformUsingBabel to true in ts-jest config. This would also give us an opportunity to introduce the ts-jest config within the jest config which can be used by #217 later.

0reactions

GeeWeecommented, May 24, 2017

Currently babel is only used when allowSyntheticDefaultImports is set to true, so it covers all cases. I imagine if we end up using babel for every transformation we will make them independent

On Wed, May 24, 2017, 20:43 jupl notifications@github.com wrote:

I’m confused on the conclusion. My understanding is that right now skipBabel is only applicable to allowSyntheticDefaultImports. If that’s the case is the plan to eventually make skipBabel be independent of allowSyntheticDefaultImports?

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Gustav Wengel