text/template
import "text/template"
Package template implements data-driven templates for generating textual output. To generate HTML output, see [html/template], which has the same interface as this package but automatically secures HTML output against certain attacks. Templates are executed by applying them to a data structure. Annotations in the template refer to elements of the data structure (typically a field of a struct or a key in a map) to control execution and derive values to be displayed. Execution of the template...
Go 1.26.1
Functions
func HTMLEscape(w io.Writer, b []byte)
HTMLEscape writes to w the escaped HTML equivalent of the plain text data b.
text/template/funcs.go:609
func HTMLEscaper(args ...any) string
HTMLEscaper returns the escaped HTML equivalent of the textual representation of its arguments.
text/template/funcs.go:649
func HTMLEscapeString(s string) string
HTMLEscapeString returns the escaped HTML equivalent of the plain text data s.
text/template/funcs.go:637
func IsTrue(val any) bool
IsTrue reports whether the value is 'true', in the sense of not the zero of its type, and whether the value has a meaningful truth value. This is the definition of truth used by if and other such actions.
text/template/exec.go:320
func JSEscape(w io.Writer, b []byte)
JSEscape writes to w the escaped JavaScript equivalent of the plain text data b.
text/template/funcs.go:669
func JSEscaper(args ...any) string
JSEscaper returns the escaped JavaScript equivalent of the textual representation of its arguments.
text/template/funcs.go:740
func JSEscapeString(s string) string
JSEscapeString returns the escaped JavaScript equivalent of the plain text data s.
text/template/funcs.go:720
func Must(t *Template, err error) *Template
Must is a helper that wraps a call to a function returning ([*Template], error) and panics if the error is non-nil. It is intended for use in variable initializations such as var t = template.Must(template.New("name").Parse("text"))
text/template/helper.go:24
func New(name string) *Template
New allocates a new, undefined template with the given name.
text/template/template.go:39
func ParseFiles(filenames ...string) (*Template, error)
ParseFiles creates a new [Template] and parses the template definitions from the named files. The returned template's name will have the base name and parsed contents of the first file. There must be at least one file. If an error occurs, parsing stops and the returned *Template is nil. When parsing multiple files with the same name in different directories, the last one mentioned will be the one that results. For instance, ParseFiles("a/foo", "b/foo") stores "b/foo" as the template named "f...
text/template/helper.go:40
func ParseFS(fsys fs.FS, patterns ...string) (*Template, error)
ParseFS is like [Template.ParseFiles] or [Template.ParseGlob] but reads from the file system fsys instead of the host operating system's file system. It accepts a list of glob patterns (see [path.Match]). (Note that most file names serve as glob patterns matching only themselves.)
text/template/helper.go:138
func ParseGlob(pattern string) (*Template, error)
ParseGlob creates a new [Template] and parses the template definitions from the files identified by the pattern. The files are matched according to the semantics of [filepath.Match], and the pattern must match at least one file. The returned template will have the [filepath.Base] name and (parsed) contents of the first file matched by the pattern. ParseGlob is equivalent to calling [ParseFiles] with the list of files matched by the pattern. When parsing multiple files with the same name in d...
text/template/helper.go:105
func URLQueryEscaper(args ...any) string
URLQueryEscaper returns the escaped value of the textual representation of its arguments in a form suitable for embedding in a URL query.
text/template/funcs.go:746
Types
type ExecError struct {
Name string // Name of template.
Err error // Pre-formatted error.
}ExecError is the custom error type returned when Execute has an error evaluating its template. (If a write error occurs, the actual error is returned; it will not be of type ExecError.)
text/template/exec.go:121
func (e ExecError) Error() string
text/template/exec.go:126
func (e ExecError) Unwrap() error
text/template/exec.go:130
type FuncMap map[string]any
FuncMap is the type of the map defining the mapping from names to functions. Each function must have either a single return value, or two return values of which the second has type error. In that case, if the second (error) return value evaluates to non-nil during execution, execution terminates and Execute returns that error. Errors returned by Execute wrap the underlying error; call [errors.AsType] to unwrap them. When template execution invokes a function with an argument list, that list...
text/template/funcs.go:33
type Template struct {
*parse.Tree
// contains filtered or unexported fields
}Template is the representation of a parsed template. The *parse.Tree field is exported only for use by [html/template] and should be treated as unexported by all other clients.
text/template/template.go:30
func (t *Template) AddParseTree(name string, tree *parse.Tree) (*Template, error)
AddParseTree associates the argument parse tree with the template t, giving it the specified name. If the template has not been defined, this tree becomes its definition. If it has been defined and already has that name, the existing definition is replaced; otherwise a new template is created, defined, and returned.
text/template/template.go:127
func (t *Template) Clone() (*Template, error)
Clone returns a duplicate of the template, including all associated templates. The actual representation is not copied, but the name space of associated templates is, so further calls to [Template.Parse] in the copy will add templates to the copy but not to the original. Clone can be used to prepare common templates and use them with variant definitions for other templates by adding the variants after the clone is made.
text/template/template.go:87
func (t *Template) DefinedTemplates() string
DefinedTemplates returns a string listing the defined templates, prefixed by the string "; defined templates are: ". If there are none, it returns the empty string. For generating an error message here and in [html/template].
text/template/exec.go:232
func (t *Template) Delims(left string, right string) *Template
Delims sets the action delimiters to the specified strings, to be used in subsequent calls to [Template.Parse], [Template.ParseFiles], or [Template.ParseGlob]. Nested template definitions will inherit the settings. An empty delimiter stands for the corresponding default: {{ or }}. The return value is the template, so calls can be chained.
text/template/template.go:162
func (t *Template) Execute(wr io.Writer, data any) error
Execute applies a parsed template to the specified data object, and writes the output to wr. If an error occurs executing the template or writing its output, execution stops, but partial results may already have been written to the output writer. A template may be executed safely in parallel, although if parallel executions share a Writer the output may be interleaved. If data is a [reflect.Value], the template applies to the concrete value that the reflect.Value holds, as in [fmt.Print].
text/template/exec.go:206
func (t *Template) ExecuteTemplate(wr io.Writer, name string, data any) error
ExecuteTemplate applies the template associated with t that has the given name to the specified data object and writes the output to wr. If an error occurs executing the template or writing its output, execution stops, but partial results may already have been written to the output writer. A template may be executed safely in parallel, although if parallel executions share a Writer the output may be interleaved.
text/template/exec.go:188
func (t *Template) Funcs(funcMap FuncMap) *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 panics if a value in the map is not a function with appropriate return type or if the name cannot be used syntactically as a function in a template. It is legal to overwrite elements of the map. The return value is the template, so calls can be chained.
text/template/template.go:175
func (t *Template) Lookup(name string) *Template
Lookup returns the template with the given name that is associated with t. It returns nil if there is no such template or the template has no definition.
text/template/template.go:186
func (t *Template) Name() string
Name returns the name of the template.
text/template/template.go:48
func (t *Template) New(name string) *Template
New allocates a new, undefined template associated with the given one and with the same delimiters. The association, which is transitive, allows one template to invoke another with a {{template}} action. Because associated templates share underlying data, template construction cannot be done safely in parallel. Once the templates are constructed, they can be executed in parallel.
text/template/template.go:59
func (t *Template) Option(opt ...string) *Template
Option sets options for the template. Options are described by strings, either a simple string or "key=value". There can be at most one equals sign in an option string. If the option string is unrecognized or otherwise invalid, Option panics. Known options: missingkey: Control the behavior during execution if a map is indexed with a key that is not present in the map. "missingkey=default" or "missingkey=invalid" The default behavior: Do nothing and continue execution. If printed, the ...
text/template/option.go:42
func (t *Template) Parse(text string) (*Template, error)
Parse parses text as a template body for t. Named template definitions ({{define ...}} or {{block ...}} statements) in text define additional templates associated with t and are removed from the definition of t itself. Templates can be redefined in successive calls to Parse. A template definition with a body containing only white space and comments is considered empty and will not replace an existing template's body. This allows using Parse to add new named template definitions without overw...
text/template/template.go:205
func (t *Template) ParseFiles(filenames ...string) (*Template, error)
ParseFiles parses the named files and associates the resulting templates with t. If an error occurs, parsing stops and the returned template is nil; otherwise it is t. There must be at least one file. Since the templates created by ParseFiles are named by the base (see [filepath.Base]) names of the argument files, t should usually have the name of one of the (base) names of the files. If it does not, depending on t's contents before calling ParseFiles, t.Execute may fail. In that case use t.E...
text/template/helper.go:55
func (t *Template) ParseFS(fsys fs.FS, patterns ...string) (*Template, error)
ParseFS is like [Template.ParseFiles] or [Template.ParseGlob] but reads from the file system fsys instead of the host operating system's file system. It accepts a list of glob patterns (see [path.Match]). (Note that most file names serve as glob patterns matching only themselves.)
text/template/helper.go:146
func (t *Template) ParseGlob(pattern string) (*Template, error)
ParseGlob parses the template definitions in the files identified by the pattern and associates the resulting templates with t. The files are matched according to the semantics of [filepath.Match], and the pattern must match at least one file. ParseGlob is equivalent to calling [Template.ParseFiles] with the list of files matched by the pattern. When parsing multiple files with the same name in different directories, the last one mentioned will be the one that results.
text/template/helper.go:117
func (t *Template) Templates() []*Template
Templates returns a slice of defined templates associated with t.
text/template/template.go:143