Use variadic args for Value factory options

Signed-off-by: Xabier Larrakoetxea <slok69@gmail.com>

widgets/linechart/internal/axes/axes.go

@@ -73,7 +73,7 @@ type YProperties struct {
 	// ScaleMode determines how the Y axis scales.
 	ScaleMode YScaleMode
 	// ValueFormatter is the formatter used to format numeric values to string representation.
-	ValueFormatter valueFormatter
+	ValueFormatter func(float64) string
 }
 
 // NewYDetails retrieves details about the Y axis required to draw it on a

widgets/linechart/internal/axes/axes_test.go

@@ -213,8 +213,8 @@ func TestY(t *testing.T) {
 				End:   image.Point{1, 2},
 				Scale: mustNewYScale(0, 3, 2, nonZeroDecimals, YScaleModeAnchored, testValueFormatter),
 				Labels: []*Label{
-					{NewFormattedValue(0, nonZeroDecimals, testValueFormatter), image.Point{0, 1}},
-					{NewFormattedValue(1.72, nonZeroDecimals, testValueFormatter), image.Point{0, 0}},
+					{NewValue(0, nonZeroDecimals, ValueFormatter(testValueFormatter)), image.Point{0, 1}},
+					{NewValue(1.72, nonZeroDecimals, ValueFormatter(testValueFormatter)), image.Point{0, 0}},
 				},
 			},
 		},

widgets/linechart/internal/axes/scale.go

@@ -69,7 +69,7 @@ type YScale struct {
 
 	// valueFormatter is the value formatter used for the labels
 	// represented by the values on the scale.
-	valueFormatter valueFormatter
+	valueFormatter func(float64) string
 }
 
 // String implements fmt.Stringer.
@@ -82,7 +82,7 @@ func (ys *YScale) String() string {
 // calculated scale, see NewValue for details.
 // Max must be greater or equal to min. The graphHeight must be a positive
 // number.
-func NewYScale(min, max float64, graphHeight, nonZeroDecimals int, mode YScaleMode, valueFormatter valueFormatter) (*YScale, error) {
+func NewYScale(min, max float64, graphHeight, nonZeroDecimals int, mode YScaleMode, valueFormatter func(float64) string) (*YScale, error) {
 	if max < min {
 		return nil, fmt.Errorf("max(%v) cannot be less than min(%v)", max, min)
 	}
@@ -199,12 +199,13 @@ func (ys *YScale) CellLabel(y int) (*Value, error) {
 // yScaleNewValue is a helper method to get new values for the y scale
 // that selects the correct value factory method  depending on the passed
 // arguments.
-func yScaleNewValue(value float64, nonZeroDecimals int, valueFormatter valueFormatter) *Value {
+func yScaleNewValue(value float64, nonZeroDecimals int, valueFormatter func(float64) string) *Value {
+	opts := []ValueOption{}
 	if valueFormatter != nil {
-		return NewFormattedValue(value, nonZeroDecimals, valueFormatter)
+		opts = append(opts, ValueFormatter(valueFormatter))
 	}
 
-	return NewValue(value, nonZeroDecimals)
+	return NewValue(value, nonZeroDecimals, opts...)
 }
 
 // XScale is the scale of the X axis.

widgets/linechart/internal/axes/scale_test.go

@@ -22,8 +22,8 @@ import (
 )
 
 // mustNewYScale returns a new YScale or panics.
-func mustNewYScale(min, max float64, graphHeight, nonZeroDecimals int, mode YScaleMode, formatter valueFormatter) *YScale {
-	s, err := NewYScale(min, max, graphHeight, nonZeroDecimals, mode, formatter)
+func mustNewYScale(min, max float64, graphHeight, nonZeroDecimals int, mode YScaleMode, valueFormatter func(float64) string) *YScale {
+	s, err := NewYScale(min, max, graphHeight, nonZeroDecimals, mode, valueFormatter)
 	if err != nil {
 		panic(err)
 	}

widgets/linechart/internal/axes/value.go

@@ -23,7 +23,30 @@ import (
 	"github.com/mum4k/termdash/internal/numbers"
 )
 
-type valueFormatter = func(float64) string
+// ValueOption is used to provide options to the NewValue function.
+type ValueOption interface {
+	// set sets the provided option.
+	set(*valueOptions)
+}
+
+type valueOptions struct {
+	formatter func(v float64) string
+}
+
+// valueOption implements ValueOption.
+type valueOption func(opts *valueOptions)
+
+// set implements ValueOption.set.
+func (vo valueOption) set(opts *valueOptions) {
+	vo(opts)
+}
+
+// ValueFormatter sets a custom formatter for the value.
+func ValueFormatter(formatter func(float64) string) ValueOption {
+	return valueOption(func(opts *valueOptions) {
+		opts.formatter = formatter
+	})
+}
 
 // Value represents one value.
 type Value struct {
@@ -38,10 +61,10 @@ type Value struct {
 	// NonZeroDecimals indicates the rounding precision used, it is provided on
 	// a call to newValue.
 	NonZeroDecimals int
-	// Formatter will format value to a string representation of the value,
-	// if Formatter is not present it will fallback to default format.
-	Formatter valueFormatter
 
+	// formatter will format value to a string representation of the value,
+	// if Formatter is not present it will fallback to default format.
+	formatter func(float64) string
 	// text value if this value was constructed using NewTextValue.
 	text string
 }
@@ -53,20 +76,19 @@ func (v *Value) String() string {
 
 // NewValue returns a new instance representing the provided value, rounding
 // the value up to the specified number of non-zero decimal places.
-func NewValue(v float64, nonZeroDecimals int) *Value {
-	return NewFormattedValue(v, nonZeroDecimals, nil)
-}
+func NewValue(v float64, nonZeroDecimals int, opts ...ValueOption) *Value {
+	opt := &valueOptions{}
+	for _, o := range opts {
+		o.set(opt)
+	}
 
-// NewFormattedValue returns a new instance representing the provided value,
-// using a value formatter.
-func NewFormattedValue(v float64, nonZeroDecimals int, formatter valueFormatter) *Value {
 	r, zd := numbers.RoundToNonZeroPlaces(v, nonZeroDecimals)
 	return &Value{
 		Value:           v,
 		Rounded:         r,
 		ZeroDecimals:    zd,
 		NonZeroDecimals: nonZeroDecimals,
-		Formatter:       formatter,
+		formatter:       opt.formatter,
 	}
 }
 
@@ -85,19 +107,19 @@ func (v *Value) Text() string {
 		return v.text
 	}
 
-	if v.Formatter != nil {
-		return v.Formatter(v.Value)
+	if v.formatter != nil {
+		return v.formatter(v.Value)
 	}
 
-	return v.defaultFormatter(v.Rounded)
+	return defaultFormatter(v.Rounded, v.NonZeroDecimals, v.ZeroDecimals)
 }
 
-func (v *Value) defaultFormatter(value float64) string {
+func defaultFormatter(value float64, nonZeroDecimals, zeroDecimals int) string {
 	if math.Ceil(value) == value {
 		return fmt.Sprintf("%.0f", value)
 	}
 
-	format := fmt.Sprintf("%%.%df", v.NonZeroDecimals+v.ZeroDecimals)
+	format := fmt.Sprintf("%%.%df", nonZeroDecimals+zeroDecimals)
 	t := fmt.Sprintf(format, value)
 	if len(t) > 10 {
 		t = fmt.Sprintf("%.2e", value)

widgets/linechart/internal/axes/value_test.go

@@ -22,10 +22,13 @@ import (
 )
 
 func TestValue(t *testing.T) {
+	formatter := func(float64) string { return "test" }
+
 	tests := []struct {
 		desc            string
 		float           float64
 		nonZeroDecimals int
+		formatter       func(float64) string
 		want            *Value
 	}{
 		{
@@ -61,11 +64,24 @@ func TestValue(t *testing.T) {
 				NonZeroDecimals: 0,
 			},
 		},
+		{
+			desc:            "formatter value when value formatter as option",
+			float:           1.01234,
+			nonZeroDecimals: 0,
+			formatter:       formatter,
+			want: &Value{
+				Value:           1.01234,
+				Rounded:         1.01234,
+				ZeroDecimals:    1,
+				NonZeroDecimals: 0,
+				formatter:       formatter,
+			},
+		},
 	}
 
 	for _, tc := range tests {
 		t.Run(tc.desc, func(t *testing.T) {
-			got := NewValue(tc.float, tc.nonZeroDecimals)
+			got := NewValue(tc.float, tc.nonZeroDecimals, ValueFormatter(tc.formatter))
 			if diff := pretty.Compare(tc.want, got); diff != "" {
 				t.Errorf("NewValue => unexpected diff (-want, +got):\n%s", diff)
 			}
@@ -124,16 +140,3 @@ func TestNewTextValue(t *testing.T) {
 		t.Errorf("v.Text => got %q, want %q", got, want)
 	}
 }
-
-func TestFormattedValue(t *testing.T) {
-	const (
-		value = 42
-		want  = "test"
-	)
-
-	v := NewFormattedValue(value, 2, func(float64) string { return "test" })
-	got := v.Text()
-	if got != want {
-		t.Errorf("v.Text => got %q, want %q", got, want)
-	}
-}