Catch error when created custome expect in jest - jestjs

Question

I created testing Helper Functions as Globals in Jest to be able to use them throughout our application in every single one of our test files.
I am going to cut this out of our testing file. I am going to go to setup-global.js file, and then I will say global.loopExpect = expect() // for looping case
global.loopExpect = (actuals) => {
return {
toContainKeys: (keys) => {
if (actuals.length > 0) {
for(var i = 0; i < actuals.length && i < 5; i++){
expect(actuals[i]).toContainKeys(keys)
}
}
}
}
}
get_array.test.js
test('check contains Book property', async () => {
loopExpect([{title: 'SOLID Principles', author: 'Uncle Bob Martin'}])
.toContainKeys(['year'])
})
And when the test is run, I should get an error because the actuals object does not containr object's year property, right .
But I get an error report on my terminal, and showing the error from at Object.toContainKeys in the file setup-global.js. Even though I want the error message on the failed test to appear at Object.toContainKeys in in the test file get_array.test.js.
How to the test file catch the error or global.loopExpect() function throwing error so JEST thinks the error coming from the test file ???

Answer 1

First, I don't think you need loopExpect, because there is a simpler and more durable way to implement this:
test('check contains Book property', async () =>
[{title: 'SOLID Principles', author: 'Uncle Bob Martin'}].forEach(book =>
expect(book).toContainKeys(['year'])
)
)
But if you really want a helper function and you need to know where the test failed, one way to know is to look at the stack trace. And if you want the error to have a different stack trace, with the line from your test file on top, then you can wrap your test in a try block, and throw a new error from the catch block.