feat: support o.OverrideOutputFormat(format)

this new method creates a copy of the existing
printers.PrinterOptions in order to override
the given output without changing the original
printers.PrinterOptions.

v1/printer_options.go

@@ -29,6 +29,29 @@ func (o *PrinterOptions) WithStreams(s IOStreams) *PrinterOptions {
 	return o
 }
 
+// OverrideOutputFormat returns a copy of the PrinterOptions with an overridden OutputFormat
+func (o *PrinterOptions) OverrideOutputFormat(output string) *PrinterOptions {
+	o2 := PrinterOptions{
+		OutputFormat: output,
+		IOStreams:    o.IOStreams,
+	}
+	if o.DefaultOutputFormat != nil {
+		o2.DefaultOutputFormat = StringPointer(*o.DefaultOutputFormat)
+	}
+	if o.TableCaption != nil {
+		o2.TableCaption = StringPointer(*o.TableCaption)
+	}
+	if o.TablePopulateFN != nil {
+		fn := *o.TablePopulateFN
+		o2.TablePopulateFN = &fn
+	}
+	if o.ItemsSelector != nil {
+		sel := *o.ItemsSelector
+		o2.ItemsSelector = &sel
+	}
+	return &o2
+}
+
 // WithDefaultOutput sets a default output format if one is not provided through a flag value
 func (o *PrinterOptions) WithDefaultOutput(output string) *PrinterOptions {
 	o.DefaultOutputFormat = &output

v1/v1_tests.go

@@ -196,5 +196,48 @@ var _ = Describe("go-printers", func() {
 				Ω(outBuf.String()).Should(Equal("stringed< the answer to the question is 42 >"))
 			})
 		})
+
+		Describe("overriding the output format", func() {
+			BeforeEach(func() {
+				o.OutputFormat = "json"
+				o.WithDefaultOutput("yaml")
+			})
+
+			It("without an override", func() {
+				testData := TestDataWithStringer{
+					TestData: TestData{
+						IntField:    42,
+						StringField: "the answer to the question",
+					},
+				}
+
+				// write via custom helpers
+				err := o.WriteOutput(testData)
+				Ω(err).Should(BeNil())
+
+				// read from the test buffer
+				Ω(outBuf.String()).Should(Equal(`{
+  "IntField": 42,
+  "StringField": "the answer to the question"
+}
+`))
+			})
+
+			It("with an override", func() {
+				testData := TestDataWithStringer{
+					TestData: TestData{
+						IntField:    42,
+						StringField: "the answer to the question",
+					},
+				}
+
+				// write via custom helpers
+				err := o.OverrideOutputFormat("text").WriteOutput(testData)
+				Ω(err).Should(BeNil())
+
+				// read from the test buffer
+				Ω(outBuf.String()).Should(Equal("stringed< the answer to the question is 42 >"))
+			})
+		})
 	})
 })