Argument of type '() => JQuery' is not assignable to parameter of type '() => boolean'

Question

I am trying to write a jasmine test case for my method, but I am facing an error:

spec.ts(163,18): error TS2345: Argument of type '() => JQuery' is not assignable to parameter of type '() => boolean'.

Can you guys tell me how to fix it? Providing my code and test case below

$('.triggerKPopUpClick').click(function() {
    if ($('#financialDocumentsGrid').data("kendoGrid")) {
        $('#financialDocumentsGrid').data("kendoGrid").dataSource.data([])
    }
    that.ContractInfoPopUpWindow.data("kendoWindow").close();
    $("html, body").css("overflow", "");
});

it('triggerKPopUpClick in head', function() {
    $('.triggerKPopUpClick').trigger('click');

    waitsFor(function() {
        return $('financialDocumentsGrid').contains('financialDocumentsGrid');
    }, 'theme switcher never loaded', 10000);
});

Answer 1

The .contains() method checks if an element is a descendant of another one.

Syntax is $.contains(parent, child) . Returns true or false .

Check your # and . on selectors too...

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EDIT

Here is an example with your code...
Notice that the elements needed for .contains() arguments must be DOM elements, not jQuery elements. That is why there is some [0] .

 it('triggerKPopUpClick in head', function() { $('.triggerKPopUpClick').trigger('click'); waitsFor(function() { return $.contains('$(#financialDocumentsGrid)[0]', ' $(#AnotherElementWhichShouldBeAChild)[0]'); }, 'theme switcher never loaded', 10000); }); 

Here's an example in CodePen .

---

So... That is aout .contains() "special" syntax.
You noticed that DOM element have to be sent to .contains argument as strings ?

Maybe you be interested in an alternative:

 $("#parent").find("#child").length > 0 

If there's an element having #child in the element #parent , that is also true .