tpl/inflect: Add the SI function to format numbers with SI notation

tpl/inflect/inflect.go

@@ -18,6 +18,7 @@ import (
 	"strconv"
 	"strings"
 
+	_humanize "github.com/dustin/go-humanize"
 	_inflect "github.com/gobuffalo/flect"
 	"github.com/spf13/cast"
 )
@@ -73,3 +74,21 @@ func (ns *Namespace) Singularize(v any) (string, error) {
 
 	return _inflect.Singularize(word), nil
 }
+
+// SI formats numbers with SI notation.
+func (ns *Namespace) SI(v any, args ...any) (string, error) {
+	number, err := cast.ToFloat64E(v)
+	if err != nil {
+		return "", err
+	}
+
+	unit := ""
+	if len(args) > 0 {
+		unit, err = cast.ToStringE(args[0])
+		if err != nil {
+			return "", err
+		}
+	}
+
+	return strings.TrimSuffix(_humanize.SI(number, unit), " "), nil
+}

tpl/inflect/inflect_test.go

@@ -47,3 +47,38 @@ func TestInflect(t *testing.T) {
 		c.Assert(result, qt.Equals, test.expect)
 	}
 }
+
+func TestSI(t *testing.T) {
+	t.Parallel()
+	c := qt.New(t)
+
+	ns := New()
+
+	for _, test := range []struct {
+		in     any
+		args   []any
+		expect any
+	}{
+		{12, []any{}, "12"},
+		{"123", []any{}, "123"},
+		{1234, []any{}, "1.234 k"},
+		{"2345", []any{}, "2.345 k"},
+		{1234000, []any{}, "1.234 M"},
+		{"2345000", []any{}, "2.345 M"},
+		{"0.00000000223", []any{"M"}, "2.23 nM"},
+		{"1000000", []any{"B"}, "1 MB"},
+		{"2.2345e-12", []any{"F"}, "2.2345 pF"},
+		{"invalid-number", []any{}, false},
+	} {
+
+		result, err := ns.SI(test.in, test.args...)
+
+		if b, ok := test.expect.(bool); ok && !b {
+			c.Assert(err, qt.Not(qt.IsNil))
+			continue
+		}
+
+		c.Assert(err, qt.IsNil)
+		c.Assert(result, qt.Equals, test.expect)
+	}
+}