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Templates Goffee functions

Custom html/template FuncMap extensions that bring Liquid-like expressiveness to Go server-side templates.

String Helpers​

capitalize​

Uppercases the first letter of a string and lowercases the rest.

<h2>{{capitalize .Title}}</h2>

truncate​

Cuts a string to at most n characters and appends … if trimmed. Designed for pipeline use — pass n first.

<p>{{.Excerpt | truncate 120}}</p>

prepend​

Adds a prefix to the beginning of a string. Designed for pipeline use — pass the prefix first.

<a href="{{.Slug | prepend "/articles/"}}">Read more</a>

strAppend​

Adds a suffix to the end of a string. Designed for pipeline use — pass the suffix first.

<a href="{{.Slug | strAppend ".html"}}">Read more</a>

split​

Divides a string into a slice of substrings by a separator. Designed for pipeline use — pass the separator first. Useful combined with range or join.

{{range split "," .TagString}}
  <span class="tag">{{.}}</span>
{{end}}

join​

Concatenates a string slice into a single string with a separator.

<p class="tags">{{join .Tags " · "}}</p>

Number Helpers​

fmtNumber​

Formats an integer or float with thousands separators using the English locale.

<span>{{fmtNumber .Views}} views</span>
<span>$ {{fmtNumber .Price}}</span>

Date & Time Helpers​

fmtDate​

Formats a time.Time value using a named layout or any custom Go layout string.

Named layoutOutput example
"short"02 Jan 2006
"long"02 January 2006
"iso"2006-01-02
"datetime"02 Jan 2006 15:04
<time>{{fmtDate .PublishedAt "short"}}</time>
<time>{{fmtDate .PublishedAt "02/01/2006"}}</time>

timeAgo​

Returns a human-readable relative time string from now ("just now", "3 hours ago", "2 days ago", etc.).

<span class="meta">Published {{timeAgo .PublishedAt}}</span>

Collection Helpers​

first​

Returns the first element of a slice, or nil if the slice is empty.

{{with first .Articles}}
  <h2>{{capitalize .Title}}</h2>
{{end}}

last​

Returns the last element of a slice, or nil if the slice is empty.

{{with last .Articles}}
  <p>Latest: {{capitalize .Title}}</p>
{{end}}

sliceOf​

Returns a sub-range of a slice from index start (inclusive) to end (exclusive).

{{range sliceOf .Articles 0 3}}
  <li>{{capitalize .Title}}</li>
{{end}}

contains​

Reports whether an item is present in a slice, or a substring exists within a string.

{{if contains .Tags "go"}}
  <span class="badge">Go</span>
{{end}}

{{if contains .Bio "engineer"}}
  <p>Engineering post</p>
{{end}}

Logic Helpers​

defaultVal​

Returns a fallback value if the given value is nil or its zero value.

<p>{{defaultVal "No subtitle" .Subtitle}}</p>

ternary​

Returns trueVal if the condition is true, falseVal otherwise. Pass the true value first, then the false value, then the condition.

<span>{{ternary "Active" "Inactive" .IsActive}}</span>

coalesce​

Returns the first non-empty, non-nil value from a list of arguments.

<h3>{{coalesce .Nickname .FullName "Anonymous"}}</h3>

Struct Helpers​

hasField​

Reports whether a struct has a field with the given name. Useful for rendering shared templates across different data types.

{{if hasField . "Subtitle"}}
  <p class="subtitle">{{.Subtitle}}</p>
{{end}}

Pipeline Chaining​

Helpers designed for pipeline use (truncate, prepend, strAppend, split) accept their configuration argument first and the input string last, so they compose naturally with |.

{{/* chain multiple helpers */}}
<td>{{.Title | capitalize | truncate 40}}</td>

{{/* build a URL from a slug */}}
<a href="{{.Slug | prepend "/blog/" | strAppend ".html"}}">
  {{.Title | capitalize}}
</a>