TypeScript can't compile tests using Testcafe version >1.6.0 if module @types/jest is in the project

[LucasMaupin]

TypeScript can't compile tests using Testcafe version >1.6.0 if module @types/jest is in the project.

When I compile the tests I get the following compilation errors:

• "Property 'expect' does not exist on type 'DoneCallback'."
• "Property 'click' does not exist on type 'DoneCallback'."
• "Property 'wait' does not exist on type 'DoneCallback'."
• "Property 'before' does not exist on type 'It'."

In this case test is of type jest.It instead of TestFn. There seems to be an issue in the declaration file index.d.ts - "Cannot redeclare block-scoped variable 'test'.ts(2451)"

[AndreyBelym]

Thank you for your report. This issue looks as a duplicate of #4405. The fix will be available in testcafe@1.6.1. If you don't mind installing pre-release versions, you can install testcafe@1.6.1-alpha.2 and test it in your environment.

[vire]

@AndreyBelym I'd put a note on this into https://github.com/DevExpress/testcafe/blob/master/docs/articles/documentation/test-api/typescript-support.md

WDYT?

[AndreyBelym]

I think it isn't necessary since this problem is fixed in testcafe@1.6.1. For those people who like to precompile their tests, it's better to put a note in @types/jest README, since jest's definitions actually cause the problem. It can be reproduced easily with other test frameworks like mocha, QUnit, etc. And we have to use workarounds to stay compatible with more popular test frameworks like jest.

[vire]

@AndreyBelym actually with

• testcafe@1.6.1
• jest@24.9.0
• @types/jest@24.0.22

I have types collision where my testcafe files work as expected because fixture and test resolve to

// node_modules/testcafe/ts-defs/index.d.ts
declare const fixture: FixtureFn;
declare const test: TestFn;

while unit test files written in jest test(...) resolve as well to

// node_modules/testcafe/ts-defs/index.d.ts
declare const fixture: FixtureFn;
declare const test: TestFn;

there are multiple options

1. not using test in jest's files 😞
2. creating typescript definition file *.d.ts workaround
3. modifying types on either @types/jest (what should be the desired definition?) or modifying testcafe definition files (that was done in testcafe@1.6.1

Do you have a suggestion how to resolve this problem?

[AndreyBelym]

You will get testcafe's definitions for test only if you start *.ts files with the testcafe command or if you import the testcafe module in other *.ts files. Only definitions from the node_modules/@types directory are loaded automatically by default when compiling any TypeScript source file. Please, create a new bug report and provide an example that can be used to reproduce the problem, or at least provide your configuration files (tsconfig.json, package.json, Gulpfile.js, etc.) and your directory structure.

[lock]

This thread has been automatically locked since it is closed and there has not been any recent activity. Please open a new issue for related bugs or feature requests. We recommend you ask TestCafe API, usage and configuration inquiries on StackOverflow.