Fix: change the logic of equality checking for Widget IDs

[ycd]

Hey Max, thanks for this great package.

Today I encountered a bug (I assume it is). When using multiple ComparisonItem, checking the equality of widgets is failing.

Reproducing the bug:

I created an ExploreWidget using Explore function.

compare, err := gogtrends.Explore(ctx, &gogtrends.ExploreRequest{
	ComparisonItems: []*gogtrends.ComparisonItem{
		{
			Keyword: keywords[0],
			Geo:     location,
			Time:    date,
		},
		{
			Keyword: keywords[1],
			Geo:     location,
			Time:    date,
		},
	},
}, "EN")

Everything works fine here, this is the output of the ExploreWidget when I iterate it.

&{APP6_UEAAAAAX9OjpNJhEVoj3prChllfkoRP9ExHVy2s fe_line_chart Interest over time TIMESERIES 0xc0004ea240}
&{APP6_UEAAAAAX9OjpHPeKZIoXpXma9ciAnznpU3g4rsb fe_multi_heat_map Compared breakdown by subregion GEO_MAP 0xc0004ea5a0}
&{ fe_text  TITLE_0 <nil>}
&{APP6_UEAAAAAX9OjpIMIbe5xddzcCMLkyJo-QiZ9jb-_ fe_geo_chart_explore Interest by subregion GEO_MAP_0 0xc0004ea900}
&{APP6_UEAAAAAX9OjpG-7Vgq0uturH_LIpbhmmlxDMXuw fe_related_searches Related queries RELATED_QUERIES_0 0xc0004eab40}
&{ fe_text  TITLE_1 <nil>}
&{APP6_UEAAAAAX9OjpBteqtm7Twc9Wkqk3ubMmg-a1XdV fe_geo_chart_explore Interest by subregion GEO_MAP_1 0xc0004eaea0}
&{APP6_UEAAAAAX9OjpGaUS8hudzB_UQgOsHU_ghvg0Wug fe_related_searches Related queries RELATED_QUERIES_1 0xc0004eb0e0}

But as you can see. when we have multiple ComparisonItem. It created IDs by adding and incrementing an integer to the end.

But in here

gogtrends/vars.go

Lines 23 to 26 in ecf6908

	intOverTimeWidgetID = "TIMESERIES"
	intOverRegionID = "GEO_MAP"
	relatedQueriesID = "RELATED_QUERIES"
	relatedTopicsID = "RELATED_TOPICS"

Everything is constant. So when I use compare[4] to get related results. It fails.

relQ, err := gogtrends.Related(ctx, compare[4], "EN")
if err != nil {
	log.Fatal(err)
}

Because it does equality checking in here.

gogtrends/gogtrends.go

Lines 251 to 254 in ecf6908

	func Related(ctx context.Context, w *ExploreWidget, hl string) ([]*RankedKeyword, error) {
	if w.ID != relatedQueriesID && w.ID != relatedTopicsID {
	return nil, ErrInvalidWidgetType
	}

Checking the prefix should do good IMO.

[ycd]

Linter says it has failed but it also says linter has found no issues, let me know if anything else needed.

golangci-lint found no issues

[groovili]

Hi, Yagiz! Thanks for your contribution. Yep, this case was not covered with a package code, so it's a nice update.
Would be good to get this case (multiple ComparisonItem's) covered with unit test, to avoid bugs in the future :)

[groovili]

@ycd thanks!