fix(lint): adhere to strict triple equality check

[ghiscoding-SE]

No description provided.

[codecov]

Codecov Report

Merging #477 into master will not change coverage.
The diff coverage is 100.00%.

@@            Coverage Diff            @@
##            master      #477   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files          148       148           
  Lines         9542      9542           
  Branches      3321      3321           
=========================================
  Hits          9542      9542           

Impacted Files	Coverage Δ
...les/angular-slickgrid/aggregators/avgAggregator.ts	100.00% <100.00%> (ø)
...les/angular-slickgrid/aggregators/maxAggregator.ts	100.00% <100.00%> (ø)
...les/angular-slickgrid/aggregators/minAggregator.ts	100.00% <100.00%> (ø)
...les/angular-slickgrid/aggregators/sumAggregator.ts	100.00% <100.00%> (ø)
...id/grouping-formatters/avgTotalsDollarFormatter.ts	100.00% <100.00%> (ø)
...lickgrid/grouping-formatters/avgTotalsFormatter.ts	100.00% <100.00%> (ø)
...rouping-formatters/avgTotalsPercentageFormatter.ts	100.00% <100.00%> (ø)
...lickgrid/grouping-formatters/maxTotalsFormatter.ts	100.00% <100.00%> (ø)
...lickgrid/grouping-formatters/minTotalsFormatter.ts	100.00% <100.00%> (ø)
...grid/grouping-formatters/sumTotalsBoldFormatter.ts	100.00% <100.00%> (ø)
... and 8 more

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