template

Documentation

Overview

Package template facilitates processing of JSON strings using Go templates. Provides additional functions not available using basic Go templates, such as coloring, and table rendering.

Index

• type Template
  • func New(w io.Writer, width int, colorEnabled bool) *Template
  • func (t *Template) Execute(input io.Reader) error
  • func (t *Template) Flush() error
  • func (t *Template) Funcs(funcMap map[string]interface{}) *Template
  • func (t *Template) Parse(tmpl string) error

Examples

• Template
• Template.Funcs

Types

type Template

type Template struct {
	// contains filtered or unexported fields
}

Template is the representation of a template.

Example

// Information about the terminal can be obtained using the [pkg/term] package.
colorEnabled := true
termWidth := 14
json := strings.NewReader(heredoc.Doc(`[
		{"number": 1, "title": "One"},
		{"number": 2, "title": "Two"}
	]`))
template := "HEADER\n\n{{range .}}{{tablerow .number .title}}{{end}}{{tablerender}}\nFOOTER"
tmpl := New(os.Stdout, termWidth, colorEnabled)
if err := tmpl.Parse(template); err != nil {
	log.Fatal(err)
}
if err := tmpl.Execute(json); err != nil {
	log.Fatal(err)
}

Output:

HEADER

1  One
2  Two

FOOTER

func New

func New(w io.Writer, width int, colorEnabled bool) *Template

New initializes a Template.

func (*Template) Execute

func (t *Template) Execute(input io.Reader) error

Execute applies the parsed template to the input and writes result to the writer the template was initialized with.

func (*Template) Flush

func (t *Template) Flush() error

Flush writes any remaining data to the writer. This is mostly useful when a templates uses the tablerow function but does not include the tablerender function at the end. If a template did not use the table functionality this is a noop.

func (*Template) Funcs

func (t *Template) Funcs(funcMap map[string]interface{}) *Template

Funcs adds the elements of the argument map to the template's function map. It must be called before the template is parsed. It is legal to overwrite elements of the map including default functions. The return value is the template, so calls can be chained.

Example

// Information about the terminal can be obtained using the [pkg/term] package.
colorEnabled := true
termWidth := 14
json := strings.NewReader(heredoc.Doc(`[
		{"num": 1, "thing": "apple"},
		{"num": 2, "thing": "orange"}
	]`))
template := "{{range .}}* {{pluralize .num .thing}}\n{{end}}"
tmpl := New(os.Stdout, termWidth, colorEnabled)
tmpl.Funcs(map[string]interface{}{
	"pluralize": func(fields ...interface{}) (string, error) {
		if l := len(fields); l != 2 {
			return "", fmt.Errorf("wrong number of args for pluralize: want 2 got %d", l)
		}
		var ok bool
		var num float64
		var thing string
		if num, ok = fields[0].(float64); !ok && num == float64(int(num)) {
			return "", fmt.Errorf("invalid value; expected int")
		}
		if thing, ok = fields[1].(string); !ok {
			return "", fmt.Errorf("invalid value; expected string")
		}
		return text.Pluralize(int(num), thing), nil
	},
})
if err := tmpl.Parse(template); err != nil {
	log.Fatal(err)
}
if err := tmpl.Execute(json); err != nil {
	log.Fatal(err)
}

Output:

* 1 apple
* 2 oranges

func (*Template) Parse

func (t *Template) Parse(tmpl string) error

Parse the given template string for use with Execute.