whitespace-eating tags backport wrapper

whitespace.go

// +build !go1.6

package main

import (
	"regexp"
	"text/template"
)

func parseTemplate(tmpl *template.Template, input string) (*template.Template, error) {
	input = wsPrefix.ReplaceAllString(input, "{{ ")
	input = wsSuffix.ReplaceAllString(input, " }}")
	return tmpl.Parse(input)
}

var (
	wsPrefix = regexp.MustCompile(`\s*{{- `)
	wsSuffix = regexp.MustCompile(` -}}\s*`)
)

whitespace_noop.go

// +build go1.6

package main

import "text/template"

func parseTemplate(tmpl *template.Template, input string) (*template.Template, error) {
	return tmpl.Parse(input)
}

whitespace_test.go

package main

import (
	"bytes"
	"testing"
	"text/template"
)

func TestWhitespaceRemoved(t *testing.T) {
	tmpl, err := parseTemplate(template.New(""), "\t{{- .VAL -}}  \n     , text")
	if err != nil {
		t.Fatalf("error parsing template: %s", err)
	}

	buf := new(bytes.Buffer)
	err = tmpl.Execute(buf, map[string]string{"VAL": "value"})
	if err != nil {
		t.Errorf("execute error: %s", err)
	}

	expected := "value, text"
	got := buf.String()
	if got != expected {
		t.Errorf("rendered string: expected %q, got %q", expected, got)
	}
}