refactor: deduplicate numericOnly and DuckDuckGo result extraction

- Extract identical numericOnly inline functions from powerball and
  megamillions into shared sites/internal/parse.NumericOnly with tests
- Extract duplicated DuckDuckGo result parsing from Search() and
  GetResults() into shared extractResults() helper

Closes #13, #14

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

sites/duckduckgo/duckduckgo.go

@@ -95,39 +95,5 @@ func (c Config) Search(ctx context.Context, b extractor.Browser, query string) (
 	}
 	defer extractor.DeferClose(doc)
 
-	var res []Result
-
-	err = doc.ForEach(`article[id^="r1-"]`, func(n extractor.Node) error {
-		var r Result
-
-		links := n.Select(`a[href][target="_self"]`)
-
-		if len(links) == 0 {
-			return nil
-		}
-
-		r.URL, err = links[0].Attr(`href`)
-
-		if err != nil {
-			return fmt.Errorf("failed to get link: %w", err)
-		}
-
-		titles := n.Select("h2")
-
-		if len(titles) != 0 {
-			r.Title, _ = titles[0].Text()
-		}
-
-		descriptions := n.Select("span > span")
-
-		if len(descriptions) != 0 {
-			r.Description, _ = descriptions[0].Text()
-		}
-
-		res = append(res, r)
-
-		return nil
-	})
-
-	return res, err
+	return extractResults(doc)
 }

sites/duckduckgo/page.go

@@ -18,9 +18,14 @@ type searchPage struct {
 }
 
 func (s searchPage) GetResults() ([]Result, error) {
+	return extractResults(s.doc)
+}
+
+// extractResults parses search results from a DuckDuckGo results page.
+func extractResults(doc extractor.Node) ([]Result, error) {
 	var res []Result
 
-	err := s.doc.ForEach(`article[id^="r1-"]`, func(n extractor.Node) error {
+	err := doc.ForEach(`article[id^="r1-"]`, func(n extractor.Node) error {
 		var r Result
 
 		links := n.Select(`a[href][target="_self"]`)

sites/internal/parse/parse.go

@@ -0,0 +1,21 @@
+package parse
+
+import "strconv"
+
+// NumericOnly extracts only digits and decimal points from a string and
+// returns the result as a float64. Returns 0 if parsing fails.
+func NumericOnly(in string) float64 {
+	var out string
+	for _, r := range in {
+		if (r >= '0' && r <= '9') || r == '.' {
+			out += string(r)
+		}
+	}
+
+	val, err := strconv.ParseFloat(out, 64)
+	if err != nil {
+		return 0
+	}
+
+	return val
+}

sites/internal/parse/parse_test.go

@@ -0,0 +1,25 @@
+package parse
+
+import "testing"
+
+func TestNumericOnly(t *testing.T) {
+	tests := []struct {
+		input string
+		want  float64
+	}{
+		{"$1.5 Billion", 1.5},
+		{"$100 Million", 100},
+		{"$200,000", 200000},
+		{"no numbers", 0},
+		{"", 0},
+		{"42", 42},
+		{"3.14159", 3.14159},
+	}
+
+	for _, tt := range tests {
+		got := NumericOnly(tt.input)
+		if got != tt.want {
+			t.Errorf("NumericOnly(%q) = %v, want %v", tt.input, got, tt.want)
+		}
+	}
+}

sites/megamillions/megamillions.go

@@ -8,6 +8,7 @@ import (
 	"time"
 
 	"gitea.stevedudenhoeffer.com/steve/go-extractor"
+	"gitea.stevedudenhoeffer.com/steve/go-extractor/sites/internal/parse"
 
 	"golang.org/x/text/currency"
 )
@@ -166,30 +167,7 @@ func getNextDrawing(_ context.Context, doc extractor.Document) (*NextDrawing, er
 
 	// jackpot is in the format of "$1.5 billion", "$100 million", or "$200,000" etc
 
-	// make one filter to only get the numeric part of the jackpot
-
-	numericOnly := func(in string) float64 {
-		var out string
-		for _, r := range in {
-			if r >= '0' && r <= '9' {
-				out += string(r)
-			}
-
-			if r == '.' {
-				out += string(r)
-			}
-		}
-
-		val, err := strconv.ParseFloat(out, 64)
-
-		if err != nil {
-			return 0
-		}
-
-		return val
-	}
-
-	numeric := numericOnly(txt)
+	numeric := parse.NumericOnly(txt)
 
 	if strings.Contains(txt, "Billion") {
 		nextDrawing.Jackpot = currency.USD.Amount(numeric * 1000000000)

sites/powerball/powerball.go

@@ -8,6 +8,7 @@ import (
 	"time"
 
 	"gitea.stevedudenhoeffer.com/steve/go-extractor"
+	"gitea.stevedudenhoeffer.com/steve/go-extractor/sites/internal/parse"
 )
 
 type Config struct {
@@ -144,30 +145,7 @@ func getNextDrawing(_ context.Context, doc extractor.Document) (*NextDrawing, er
 
 	// jackpot is in the format of "$1.5 billion", "$100 million", or "$200,000" etc
 
-	// make one filter to only get the numeric part of the jackpot
-
-	numericOnly := func(in string) float64 {
-		var out string
-		for _, r := range in {
-			if r >= '0' && r <= '9' {
-				out += string(r)
-			}
-
-			if r == '.' {
-				out += string(r)
-			}
-		}
-
-		val, err := strconv.ParseFloat(out, 64)
-
-		if err != nil {
-			return 0
-		}
-
-		return val
-	}
-
-	numeric := numericOnly(txt)
+	numeric := parse.NumericOnly(txt)
 
 	if strings.Contains(txt, "Billion") {
 		nextDrawing.JackpotDollars = int(numeric * 1000000000)