add null handling for item label properties

[gatanaso]

This PR fixes #680 of the vaadin-combo-box failing to render when an item property used as a label path has a null value.

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This change is 

[CLAassistant]

All committers have signed the CLA.

[coveralls]

Pull Request Test Coverage Report for Build 3369

• 1 of 1 (100.0%) changed or added relevant line in 1 file are covered.
• 3 unchanged lines in 2 files lost coverage.
• Overall coverage decreased (-0.6%) to 90.514%

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Files with Coverage Reduction	New Missed Lines	%
src/vaadin-combo-box-dropdown.html	1	97.35%
src/vaadin-combo-box-dropdown-wrapper.html	2	76.67%

Totals
Change from base Build 3363:	-0.6%
Covered Lines:	475
Relevant Lines:	503

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💛 - Coveralls

[manolo]

Reviewable status: 0 of 2 files reviewed, 1 unresolved discussion (waiting on @gatanaso)

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src/vaadin-combo-box-dropdown-wrapper.html, line 262 at r1 (raw file):

        if (label === undefined) {
          label = item ? item.toString() : '';
        } else if (label === null) {

I feel that the correct code here should be like in the line above, set item.toString if item exists like it does with undefined.

[gatanaso]

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src/vaadin-combo-box-dropdown-wrapper.html, line 262 at r1 (raw file):

Previously, manolo (Manuel Carrasco Moñino) wrote…

I feel that the correct code here should be like in the line above, set item.toString if item exists like it does with undefined.

Thanks for the review. I have updated the PR.

[manolo]

Reviewable status: 0 of 2 files reviewed, all discussions resolved

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src/vaadin-combo-box-dropdown-wrapper.html, line 262 at r1 (raw file):

Previously, gatanaso (Goran) wrote…

Thanks for the review. I have updated the PR.

Tip: if (label === undefined || label === null) can be rewritten as if (label == null) of if (label == undefined) , but not a blocker.

[yuriy-fix]

Reviewed 2 of 2 files at r2.
Reviewable status: complete! all files reviewed, all discussions resolved

[yuriy-fix]

Rebase on current master, should help with passing the build.

[manolo]

Reviewed 2 of 2 files at r2.
Reviewable status: complete! all files reviewed, all discussions resolved

[manolo]

Good Job! thanks for contributing

Reviewable status: complete! all files reviewed, all discussions resolved