Statement coverage of external script is 0

[linden5]

I found that if configured collectCoverageFrom for jest, the statement coverage of external script goes to 0.
Thought I can solve the problem by adding ignore patterns in the collectCoverageFrom, is it possible to solve this problem in other ways? Since I have to move source files around to make the coverage match my expectation.

[drudkovskiy]

@linden5
There's a workaround for this issue.
Instead of defining externals scripts using src you can import and then immediately export it.
Then the coverage works fine for such type of components.

So instead of this:
<script src="myComponent.js"></script>
you can write this:

<script>
  import MyComponent from './myComponent.js';
  export default MyComponent;
</script>```

[eddyerburgh]

Is this issue with 3.x or with 4.x@beta?

[linden5]

This issue is with vue-jest@3.0.5 and jest@23.6.0. Repro

[lancygoyal]

To fix this issue, do changes like below -

-<script lang="ts" src="./Button.ts" />
+<script>
+import Button from './Button.ts';
+export default Button;
+</script>