table: markdown padding for human-friendly output; fixes #402

table/render_markdown.go

@@ -51,22 +51,49 @@
 		if colIdx < len(row) {
 			colStr = row[colIdx]
 		}
-		out.WriteRune(' ')
 		colStr = strings.ReplaceAll(colStr, "|", "\\|")
 		colStr = strings.ReplaceAll(colStr, "\n", "<br/>")
-		out.WriteString(colStr)
-		out.WriteRune(' ')
+		if t.style.Markdown.PadContent {
+			out.WriteRune(' ')
+			align := t.getAlign(colIdx, hint)
+			out.WriteString(align.Apply(colStr, t.maxColumnLengths[colIdx]))
+			out.WriteRune(' ')
+		} else {
+			out.WriteRune(' ')
+			out.WriteString(colStr)
+			out.WriteRune(' ')
+		}
 		out.WriteRune('|')
 	}
 }
 
 func (t *Table) markdownRenderRowAutoIndex(out *strings.Builder, colIdx int, hint renderHint) {
 	if colIdx == 0 && t.autoIndex {
-		out.WriteRune(' ')
 		if hint.isSeparatorRow {
-			out.WriteString("---:")
+			if t.style.Markdown.PadContent {
+				out.WriteString(" " + strings.Repeat("-", t.autoIndexVIndexMaxLength) + ":")
+			} else {
+				out.WriteRune(' ')
+				out.WriteString("---:")
+			}
 		} else if hint.isRegularRow() {
-			fmt.Fprintf(out, "%d ", hint.rowNumber)
+			if t.style.Markdown.PadContent {
+				rowNumStr := fmt.Sprint(hint.rowNumber)
+				out.WriteRune(' ')
+				fmt.Fprintf(out, "%*s", t.autoIndexVIndexMaxLength, rowNumStr)
+				out.WriteRune(' ')
+			} else {
+				out.WriteRune(' ')
+				fmt.Fprintf(out, "%d ", hint.rowNumber)
+			}
+		} else {
+			if t.style.Markdown.PadContent {
+				out.WriteRune(' ')
+				out.WriteString(strings.Repeat(" ", t.autoIndexVIndexMaxLength))
+				out.WriteRune(' ')
+			} else {
+				out.WriteRune(' ')
+			}
 		}
 		out.WriteRune('|')
 	}
@@ -107,7 +134,12 @@
 	for colIdx := 0; colIdx < t.numColumns; colIdx++ {
 		t.markdownRenderRowAutoIndex(out, colIdx, hint)
 
-		out.WriteString(t.getAlign(colIdx, hint).MarkdownProperty())
+		align := t.getAlign(colIdx, hint)
+		if t.style.Markdown.PadContent {
+			out.WriteString(align.MarkdownProperty(t.maxColumnLengths[colIdx]))
+		} else {
+			out.WriteString(align.MarkdownProperty())
+		}
 		out.WriteRune('|')
 	}
 }

table/render_markdown_test.go

@@ -65,6 +65,66 @@ func TestTable_RenderMarkdown_AutoIndex(t *testing.T) {
 | | AF | BF | CF | DF | EF | FF | GF | HF | IF | JF |`)
 }
 
+func TestTable_RenderMarkdown_Padded(t *testing.T) {
+	tw := NewWriter()
+	tw.AppendHeader(testHeader)
+	tw.AppendRows(testRows)
+	tw.AppendRow(testRowNewLines)
+	tw.AppendRow(testRowPipes)
+	tw.AppendFooter(testFooter)
+	tw.SetCaption(testCaption)
+	tw.SetTitle(testTitle1)
+	tw.Style().Markdown.PadContent = true
+
+	compareOutput(t, tw.RenderMarkdown(), `
+# Game of Thrones
+|   # | First Name | Last Name | Salary |                             |
+| ---:| ---------- | --------- | ------:| --------------------------- |
+|   1 | Arya       | Stark     |   3000 |                             |
+|  20 | Jon        | Snow      |   2000 | You know nothing, Jon Snow! |
+| 300 | Tyrion     | Lannister |   5000 |                             |
+|   0 | Valar      | Morghulis |      0 | Faceless<br/>Men            |
+|   0 | Valar      | Morghulis |      0 | Faceless\|Men               |
+|     |            | Total     |  10000 |                             |
+_A Song of Ice and Fire_`)
+}
+
+func TestTable_RenderMarkdown_Padded_AutoIndex(t *testing.T) {
+	tw := NewWriter()
+	for rowIdx := 0; rowIdx < 10; rowIdx++ {
+		row := make(Row, 10)
+		for colIdx := 0; colIdx < 10; colIdx++ {
+			row[colIdx] = fmt.Sprintf("%s%d", AutoIndexColumnID(colIdx), rowIdx+1)
+		}
+		tw.AppendRow(row)
+	}
+	for rowIdx := 0; rowIdx < 1; rowIdx++ {
+		row := make(Row, 10)
+		for colIdx := 0; colIdx < 10; colIdx++ {
+			row[colIdx] = AutoIndexColumnID(colIdx) + "F"
+		}
+		tw.AppendFooter(row)
+	}
+	tw.SetAutoIndex(true)
+	tw.SetStyle(StyleLight)
+	tw.Style().Markdown.PadContent = true
+
+	compareOutput(t, tw.RenderMarkdown(), `
+|    |  A  |  B  |  C  |  D  |  E  |  F  |  G  |  H  |  I  |  J  |
+| --:| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
+|  1 | A1  | B1  | C1  | D1  | E1  | F1  | G1  | H1  | I1  | J1  |
+|  2 | A2  | B2  | C2  | D2  | E2  | F2  | G2  | H2  | I2  | J2  |
+|  3 | A3  | B3  | C3  | D3  | E3  | F3  | G3  | H3  | I3  | J3  |
+|  4 | A4  | B4  | C4  | D4  | E4  | F4  | G4  | H4  | I4  | J4  |
+|  5 | A5  | B5  | C5  | D5  | E5  | F5  | G5  | H5  | I5  | J5  |
+|  6 | A6  | B6  | C6  | D6  | E6  | F6  | G6  | H6  | I6  | J6  |
+|  7 | A7  | B7  | C7  | D7  | E7  | F7  | G7  | H7  | I7  | J7  |
+|  8 | A8  | B8  | C8  | D8  | E8  | F8  | G8  | H8  | I8  | J8  |
+|  9 | A9  | B9  | C9  | D9  | E9  | F9  | G9  | H9  | I9  | J9  |
+| 10 | A10 | B10 | C10 | D10 | E10 | F10 | G10 | H10 | I10 | J10 |
+|    | AF  | BF  | CF  | DF  | EF  | FF  | GF  | HF  | IF  | JF  |`)
+}
+
 func TestTable_RenderMarkdown_Empty(t *testing.T) {
 	tw := NewWriter()
 	assert.Empty(t, tw.RenderMarkdown())

table/style.go

@@ -3,14 +3,15 @@ package table
 // Style declares how to render the Table and provides very fine-grained control
 // on how the Table gets rendered on the Console.
 type Style struct {
-	Name    string        // name of the Style
-	Box     BoxStyle      // characters to use for the boxes
-	Color   ColorOptions  // colors to use for the rows and columns
-	Format  FormatOptions // formatting options for the rows and columns
-	HTML    HTMLOptions   // rendering options for HTML mode
-	Options Options       // misc. options for the table
-	Size    SizeOptions   // size (width) options for the table
-	Title   TitleOptions  // formation options for the title text
+	Name     string          // name of the Style
+	Box      BoxStyle        // characters to use for the boxes
+	Color    ColorOptions    // colors to use for the rows and columns
+	Format   FormatOptions   // formatting options for the rows and columns
+	HTML     HTMLOptions     // rendering options for HTML mode
+	Markdown MarkdownOptions // rendering options for Markdown mode
+	Options  Options         // misc. options for the table
+	Size     SizeOptions     // size (width) options for the table
+	Title    TitleOptions    // formation options for the title text
 }
 
 var (

table/style_markdown.go

@@ -0,0 +1,25 @@
+package table
+
+// MarkdownOptions defines options to control Markdown rendering.
+type MarkdownOptions struct {
+	// PadContent pads each column content to match the longest content in
+	// the column, and extends the separator dashes to match. This makes the
+	// raw Markdown source more readable without affecting the rendered
+	// output.
+	//
+	// When disabled (default):
+	//  | # | First Name | Last Name | Salary |  |
+	//  | ---:| --- | --- | ---:| --- |
+	//  | 1 | Arya | Stark | 3000 |  |
+	//
+	// When enabled:
+	//  | # | First Name | Last Name | Salary |                             |
+	//  | ---:| ---------- | --------- | ------:| --------------------------- |
+	//  | 1 | Arya       | Stark     |   3000 |                             |
+	PadContent bool
+}
+
+var (
+	// DefaultMarkdownOptions defines sensible Markdown rendering defaults.
+	DefaultMarkdownOptions = MarkdownOptions{}
+)

text/align.go

@@ -76,16 +76,24 @@ func (a Align) HTMLProperty() string {
 }
 
 // MarkdownProperty returns the equivalent Markdown horizontal-align separator.
-func (a Align) MarkdownProperty() string {
+// An optional minLength can be provided to extend the dashes to match the
+// column content width; the result will be max(minLength, 3)+2 wide (including
+// leading/trailing space or colon). Without minLength (or 0), it defaults to 3.
+func (a Align) MarkdownProperty(minLength ...int) string {
+	length := 3
+	if len(minLength) > 0 && minLength[0] > length {
+		length = minLength[0]
+	}
+	dashes := strings.Repeat("-", length)
 	switch a {
 	case AlignLeft:
-		return ":--- "
+		return ":" + dashes + " "
 	case AlignCenter:
-		return ":---:"
+		return ":" + dashes + ":"
 	case AlignRight:
-		return " ---:"
+		return " " + dashes + ":"
 	default:
-		return " --- "
+		return " " + dashes + " "
 	}
 }
 

text/align_test.go

@@ -151,3 +151,16 @@ func TestAlign_MarkdownProperty(t *testing.T) {
 		assert.Contains(t, align.MarkdownProperty(), markdownSeparator)
 	}
 }
+
+func TestAlign_MarkdownProperty_WithMinLength(t *testing.T) {
+	assert.Equal(t, " ---------- ", AlignDefault.MarkdownProperty(10))
+	assert.Equal(t, ":---------- ", AlignLeft.MarkdownProperty(10))
+	assert.Equal(t, ":----------:", AlignCenter.MarkdownProperty(10))
+	assert.Equal(t, " ---------- ", AlignJustify.MarkdownProperty(10))
+	assert.Equal(t, " ----------:", AlignRight.MarkdownProperty(10))
+
+	// minimum width of 3
+	assert.Equal(t, " --- ", AlignDefault.MarkdownProperty(1))
+	assert.Equal(t, " --- ", AlignDefault.MarkdownProperty(3))
+	assert.Equal(t, " ---- ", AlignDefault.MarkdownProperty(4))
+}