First commit

vendor/github.com/tdewolff/minify/js/js.go

@@ -0,0 +1,88 @@
+// Package js minifies ECMAScript5.1 following the specifications at http://www.ecma-international.org/ecma-262/5.1/.
+package js // import "github.com/tdewolff/minify/js"
+
+import (
+	"io"
+
+	"github.com/tdewolff/minify"
+	"github.com/tdewolff/parse"
+	"github.com/tdewolff/parse/js"
+)
+
+var (
+	spaceBytes   = []byte(" ")
+	newlineBytes = []byte("\n")
+)
+
+////////////////////////////////////////////////////////////////
+
+// DefaultMinifier is the default minifier.
+var DefaultMinifier = &Minifier{}
+
+// Minifier is a JS minifier.
+type Minifier struct{}
+
+// Minify minifies JS data, it reads from r and writes to w.
+func Minify(m *minify.M, w io.Writer, r io.Reader, params map[string]string) error {
+	return DefaultMinifier.Minify(m, w, r, params)
+}
+
+// Minify minifies JS data, it reads from r and writes to w.
+func (o *Minifier) Minify(_ *minify.M, w io.Writer, r io.Reader, _ map[string]string) error {
+	prev := js.LineTerminatorToken
+	prevLast := byte(' ')
+	lineTerminatorQueued := false
+	whitespaceQueued := false
+
+	l := js.NewLexer(r)
+	defer l.Restore()
+
+	for {
+		tt, data := l.Next()
+		if tt == js.ErrorToken {
+			if l.Err() != io.EOF {
+				return l.Err()
+			}
+			return nil
+		} else if tt == js.LineTerminatorToken {
+			lineTerminatorQueued = true
+		} else if tt == js.WhitespaceToken {
+			whitespaceQueued = true
+		} else if tt == js.CommentToken {
+			if len(data) > 5 && data[1] == '*' && data[2] == '!' {
+				if _, err := w.Write(data[:3]); err != nil {
+					return err
+				}
+				comment := parse.TrimWhitespace(parse.ReplaceMultipleWhitespace(data[3 : len(data)-2]))
+				if _, err := w.Write(comment); err != nil {
+					return err
+				}
+				if _, err := w.Write(data[len(data)-2:]); err != nil {
+					return err
+				}
+			}
+		} else {
+			first := data[0]
+			if (prev == js.IdentifierToken || prev == js.NumericToken || prev == js.PunctuatorToken || prev == js.StringToken || prev == js.RegexpToken) &&
+				(tt == js.IdentifierToken || tt == js.NumericToken || tt == js.StringToken || tt == js.PunctuatorToken || tt == js.RegexpToken) {
+				if lineTerminatorQueued && (prev != js.PunctuatorToken || prevLast == '}' || prevLast == ']' || prevLast == ')' || prevLast == '+' || prevLast == '-' || prevLast == '"' || prevLast == '\'') &&
+					(tt != js.PunctuatorToken || first == '{' || first == '[' || first == '(' || first == '+' || first == '-' || first == '!' || first == '~') {
+					if _, err := w.Write(newlineBytes); err != nil {
+						return err
+					}
+				} else if whitespaceQueued && (prev != js.StringToken && prev != js.PunctuatorToken && tt != js.PunctuatorToken || (prevLast == '+' || prevLast == '-') && first == prevLast) {
+					if _, err := w.Write(spaceBytes); err != nil {
+						return err
+					}
+				}
+			}
+			if _, err := w.Write(data); err != nil {
+				return err
+			}
+			prev = tt
+			prevLast = data[len(data)-1]
+			lineTerminatorQueued = false
+			whitespaceQueued = false
+		}
+	}
+}