/
js.go
57 lines (53 loc) · 1.96 KB
/
js.go
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// 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/js"
)
var (
spaceBytes = []byte(" ")
newlineBytes = []byte("\n")
)
// Minify minifies JS data, it reads from r and writes to w.
func Minify(_ minify.Minifier, _ string, w io.Writer, r io.Reader) error {
l := js.NewLexer(r)
prev := js.LineTerminatorToken
prevLast := byte(' ')
lineTerminatorQueued := false
whitespaceQueued := false
for {
tt, text, n := l.Next()
l.Free(n)
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 {
first := text[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.PunctuatorToken || tt == js.RegexpToken) {
if lineTerminatorQueued && (prev != js.PunctuatorToken || prevLast == '}' || prevLast == ']' || prevLast == ')' || prevLast == '+' || prevLast == '-' || prevLast == '"' || prevLast == '\'') && (tt != js.PunctuatorToken || 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(text); err != nil {
return err
}
prev = tt
prevLast = text[len(text)-1]
lineTerminatorQueued = false
whitespaceQueued = false
}
}
}