Go Template Syntax Cheatsheet

Basic Syntax

Syntax	Description	Example
{{.}}	The current value context	Hello, {{.}}!
{{.Field}}	Access struct field or map key	Name: {{.Name}}
{{.Method}}	Call a method on context	Age: {{.GetAge}}
{{/* comment */}}	Comment (not rendered)	{{/* This is a comment */}}
{{- .}}	Trim whitespace before	{{- .Name}} (remove whitespace before)
{{.}} -}}	Trim whitespace after	{{.Name -}} (remove whitespace after)

Variables

Syntax	Description	Example
{{$name := value}}	Define a variable	{{$name := "John"}}
{{$name}}	Use a variable	Hello, {{$name}}!
{{$variable := .Field}}	Store field in variable	{{$email := .Email}}
{{with $x := .Field}}...{{end}}	Define and with	{{with $user := .User}}{{$user.Name}}{{end}}

Control Structures

Conditionals

Syntax	Description	Example
{{if .Condition}}...{{end}}	Simple if	{{if .LoggedIn}}Welcome!{{end}}
{{if .Condition}}...{{else}}...{{end}}	If/else	{{if .LoggedIn}}Welcome!{{else}}Please login{{end}}
{{if .Cond1}}...{{else if .Cond2}}...{{else}}...{{end}}	If/else if/else	{{if .IsAdmin}}Admin{{else if .IsMember}}Member{{else}}Guest{{end}}

Loops

Syntax	Description	Example
{{range .Items}}...{{end}}	Loop over array/slice/map	{{range .Users}}{{.Name}}{{end}}
{{range $index, $element := .Items}}...{{end}}	Loop with index	{{range $i, $user := .Users}}{{$i}}: {{$user.Name}}{{end}}
{{range $key, $value := .Map}}...{{end}}	Loop over map	{{range $k, $v := .Data}}{{$k}}: {{$v}}{{end}}
{{range .Items}}...{{else}}...{{end}}	Range with empty case	{{range .Users}}{{.Name}}{{else}}No users found{{end}}

Context Control

Syntax	Description	Example
{{with .Field}}...{{end}}	Changes dot	{{with .User}}Name: {{.Name}}{{end}}
{{with .Field}}...{{else}}...{{end}}	With/else	{{with .User}}Name: {{.Name}}{{else}}No user found{{end}}

Template Composition

Syntax	Description	Example
{{define "name"}}...{{end}}	Define a named template	{{define "header"}}...{{end}}
{{template "name" .}}	Include template with current context	{{template "header" .}}
{{template "name" .Field}}	Include template with different context	{{template "userInfo" .User}}
{{block "name" .}}...{{end}}	Define a template with default content	{{block "content" .}}Default content{{end}}

Functions and Pipelines

Syntax	Description	Example
{{func .}}	Call function with single argument	{{len .Items}}
{{func arg1 arg2}}	Call function with multiple arguments	{{eq .Name "John"}}
`{{.	func}}`	Pipe value to function
`{{.	func1	func2}}`
`{{.Field	func1	func2}}`

Built-in Functions

Comparison

Function	Description	Example
eq	Equal	{{if eq .Status "active"}}...{{end}}
ne	Not equal	{{if ne .Status "disabled"}}...{{end}}
lt	Less than	{{if lt .Count 5}}...{{end}}
le	Less than or equal	{{if le .Count 10}}...{{end}}
gt	Greater than	{{if gt .Price 100}}...{{end}}
ge	Greater than or equal	{{if ge .Age 18}}...{{end}}

Logical Operations

Function	Description	Example
and	Logical AND	{{if and .LoggedIn .IsAdmin}}...{{end}}
or	Logical OR	{{if or .IsAdmin .IsModerator}}...{{end}}
not	Logical NOT	{{if not .IsDisabled}}...{{end}}

Data Manipulation

Function	Description	Example
len	Length of array/slice/map/string	{{len .Items}}
index	Get element at index	{{index .Users 0}}
slice	Slice an array	{{slice .Items 0 5}}
print	Concatenate and print	{{print "Hello" "World"}}
printf	Formatted print	{{printf "%.2f" .Price}}
println	Print with newline	{{println .Message}}

Text/HTML Context

Package	Description	Example
text/template	General text processing	import "text/template"
html/template	HTML-specific with auto-escaping	import "html/template"

HTML Template Types

Type	Description	Example
template.HTML	Unescaped HTML	template.HTML("<b>Bold</b>")
template.CSS	Unescaped CSS	template.CSS("color: red;")
template.JS	Unescaped JavaScript	template.JS("alert('Hello')")
template.URL	Unescaped URL	template.URL("https://example.com")
template.Srcset	Unescaped srcset attribute	template.Srcset("img.jpg 1x")

Common Template Patterns

Layout with Blocks

// base.tmpl
<!DOCTYPE html>
<html>
<head>
    <title>{{block "title" .}}Default Title{{end}}</title>
</head>
<body>
    <header>{{block "header" .}}Default Header{{end}}</header>
    <main>{{block "content" .}}Default Content{{end}}</main>
    <footer>{{block "footer" .}}Default Footer{{end}}</footer>
</body>
</html>
 
// page.tmpl
{{define "title"}}Page Title{{end}}
{{define "content"}}
    <h1>Custom Content</h1>
    <p>This is the page content.</p>
{{end}}

Reusable Components

// components.tmpl
{{define "button"}}
<button class="btn {{.Class}}" type="{{.Type}}">{{.Text}}</button>
{{end}}
 
// Usage:
{{template "button" dict "Class" "primary" "Type" "submit" "Text" "Save"}}

Pagination

{{if gt .TotalPages 1}}
<div class="pagination">
    {{if .HasPrevious}}
    <a href="?page={{.PrevPage}}">&laquo; Previous</a>
    {{else}}
    <span class="disabled">&laquo; Previous</span>
    {{end}}
    
    {{range $i := .PageNumbers}}
        {{if eq $i $.CurrentPage}}
        <span class="current">{{$i}}</span>
        {{else}}
        <a href="?page={{$i}}">{{$i}}</a>
        {{end}}
    {{end}}
    
    {{if .HasNext}}
    <a href="?page={{.NextPage}}">Next &raquo;</a>
    {{else}}
    <span class="disabled">Next &raquo;</span>
    {{end}}
</div>
{{end}}

Form Field Rendering

{{define "field"}}
<div class="form-group {{if .Error}}has-error{{end}}">
    <label for="{{.Name}}">{{.Label}}{{if .Required}} *{{end}}</label>
    <input 
        type="{{.Type}}" 
        name="{{.Name}}" 
        id="{{.Name}}" 
        value="{{.Value}}" 
        {{if .Required}}required{{end}}
    >
    {{if .Error}}
    <div class="error">{{.Error}}</div>
    {{end}}
</div>
{{end}}
 
// Usage:
{{template "field" dict "Name" "email" "Label" "Email Address" "Type" "email" "Value" .Email "Required" true "Error" .Errors.email}}

Error Handling

// Parse template with error handling
tmpl, err := template.New("example").Parse(templateText)
if err != nil {
    // Handle parsing error
    log.Fatal("Template parsing error:", err)
}
 
// Execute template with error handling
err = tmpl.Execute(outputWriter, data)
if err != nil {
    // Handle execution error
    log.Fatal("Template execution error:", err)
}
 
// Use template.Must for templates that must be valid
var tmpl = template.Must(template.New("example").Parse(templateText))

Using template.FuncMap

funcMap := template.FuncMap{
    "upper": strings.ToUpper,
    "lower": strings.ToLower,
    "title": strings.Title,
    "add": func(a, b int) int {
        return a + b
    },
    "formatDate": func(t time.Time) string {
        return t.Format("Jan 02, 2006")
    },
}
 
tmpl := template.New("example").Funcs(funcMap)
tmpl, err := tmpl.Parse(templateText)

Template Helper Structs

// Define helper methods on types
type User struct {
    FirstName string
    LastName  string
    BirthDate time.Time
}
 
func (u User) FullName() string {
    return u.FirstName + " " + u.LastName
}
 
func (u User) Age() int {
    return int(time.Since(u.BirthDate).Hours() / 24 / 365)
}
 
// In template:
{{.FullName}} (Age: {{.Age}})