in internal/backport/html/template/escape.go [718:783]
func (e *escaper) escapeText(c context, n *parse.TextNode) context {
s, written, i, b := n.Text, 0, 0, new(bytes.Buffer)
for i != len(s) {
c1, nread := contextAfterText(c, s[i:])
i1 := i + nread
if c.state == stateText || c.state == stateRCDATA {
end := i1
if c1.state != c.state {
for j := end - 1; j >= i; j-- {
if s[j] == '<' {
end = j
break
}
}
}
for j := i; j < end; j++ {
if s[j] == '<' && !bytes.HasPrefix(bytes.ToUpper(s[j:]), doctypeBytes) {
b.Write(s[written:j])
b.WriteString("<")
written = j + 1
}
}
} else if isComment(c.state) && c.delim == delimNone {
switch c.state {
case stateJSBlockCmt:
// https://es5.github.com/#x7.4:
// "Comments behave like white space and are
// discarded except that, if a MultiLineComment
// contains a line terminator character, then
// the entire comment is considered to be a
// LineTerminator for purposes of parsing by
// the syntactic grammar."
if bytes.ContainsAny(s[written:i1], "\n\r\u2028\u2029") {
b.WriteByte('\n')
} else {
b.WriteByte(' ')
}
case stateCSSBlockCmt:
b.WriteByte(' ')
}
written = i1
}
if c.state != c1.state && isComment(c1.state) && c1.delim == delimNone {
// Preserve the portion between written and the comment start.
cs := i1 - 2
if c1.state == stateHTMLCmt {
// "<!--" instead of "/*" or "//"
cs -= 2
}
b.Write(s[written:cs])
written = i1
}
if i == i1 && c.state == c1.state {
panic(fmt.Sprintf("infinite loop from %v to %v on %q..%q", c, c1, s[:i], s[i:]))
}
c, i = c1, i1
}
if written != 0 && c.state != stateError {
if !isComment(c.state) || c.delim != delimNone {
b.Write(n.Text[written:])
}
e.editTextNode(n, b.Bytes())
}
return c
}