This close #2151, streaming writer can set cell default value

Change-Id: If019aea806b9527937a9fe8d90050d2ef3d783b0
Signed-off-by: mengzhongyuan <mengzhongyuan@bytedance.com>

Author: mengzhongyuan

cell.go

@@ -571,6 +571,10 @@ func (c *xlsxC) getCellBool(f *File, raw bool) (string, error) {
 	return f.formattedValue(c, raw, CellTypeBool)
 }
 
+// SetCellDefaultValue is a type for setCellDefault function, pass this type data,  setCellDefault will be used to
+// perform the write operation.
+type SetCellDefaultValue string
+
 // setCellDefault prepares cell type and string type cell value by a given
 // string.
 func (c *xlsxC) setCellDefault(value string) {
@@ -580,7 +584,8 @@ func (c *xlsxC) setCellDefault(value string) {
 			c.IS.T.Val = value
 			return
 		}
-		c.T, c.V, c.IS = value, value, nil
+
+		c.T, c.V, c.IS = "", "", nil // I modify this to set c.T = "" explicitly to avoid misunderstanding of c.Type can be value
 		return
 	}
 	c.T, c.V = "", value

stream.go

@@ -568,6 +568,8 @@ func (sw *StreamWriter) setCellValFunc(c *xlsxC, val interface{}) error {
 	case []RichTextRun:
 		c.T, c.IS = "inlineStr", &xlsxSI{}
 		c.IS.R, err = setRichText(val)
+	case SetCellDefaultValue:
+		c.setCellDefault(string(val))
 	default:
 		c.setCellValue(fmt.Sprint(val))
 	}

stream_test.go

@@ -408,6 +408,8 @@ func TestStreamSetCellValFunc(t *testing.T) {
 		true,
 		nil,
 		complex64(5 + 10i),
+		SetCellDefaultValue("100.1588"),
+		SetCellDefaultValue(" Hello"),
 	} {
 		assert.NoError(t, sw.setCellValFunc(c, val))
 	}