A template action is a Go command or data expression enclosed in double curly brackets, such as {{.Title}}. Actions insert values into templates and can also perform logic, iteration, formatting, and other operations. section 9.1.1 section 9.1.2
Actions can connect operations into pipelines with |. Each operation receives the previous result as its final argument, allowing expressions such as {{.Date | dateFormat "Jan 2, 2006"}}. section 9.1.2
Common template-action uses include:
- Render struct fields, as with {{.Title}} and {{.Content}}. section 9.1.1
- Iterate over data with range and end, producing repeated HTML for each comment. section 9.1.1
- Format values through built-in or custom functions, such as dateFormat. section 9.1.2
- Escape inserted data according to its HTML context when using html/template. section 9.1.1
Formatting a date through an action pipeline
Register a Go function through template.FuncMap and t.Funcs(funcMap), then use {{.Date | dateFormat "Jan 2, 2006"}} in the template. The date value flows into dateFormat before reaching the output. section 9.1.2
Listing 9.1 A simple HTML template
<!DOCTYPE HTML>
<html>
<head>
<meta charset="utf-8">
<title>{{.Title}}</title> #1
</head>
<body>
<h1>{{.Title}}</h1> #2
<p>{{.Content}}</p> #2
</body>
</html>
A complete HTML template shows actions embedded alongside ordinary markup, including field rendering in the title, heading, and paragraph. section 9.1.1
