package js // import "github.com/tdewolff/minify/js"

import (

"io"

"github.com/tdewolff/minify"

"github.com/tdewolff/parse/js"

)

// Minify minifies JS files, it reads from r and writes to w.

func Minify(_ minify.Minifier, _ string, w io.Writer, r io.Reader) error {

z := js.NewTokenizer(r)

lineTerminatorQueued := false

whitespaceQueued := false

prev := js.LineTerminatorToken

prevLast := byte(' ')

for {

tt, text := z.Next()

if tt == js.ErrorToken {

if z.Err() != io.EOF {

return z.Err()

}

return nil

} else if tt == js.CommentToken {

continue

}

if tt == js.LineTerminatorToken {

lineTerminatorQueued = true

continue

} else if tt == js.WhitespaceToken {

whitespaceQueued = true

continue

} else {

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 && (tt != js.PunctuatorToken || first == '{' || first == '[' || first == '(' || first == '+' || first == '-') && (prev != js.PunctuatorToken || prevLast == '}' || prevLast == ']' || prevLast == ')' || prevLast == '+' || prevLast == '-' || prevLast == '"' || prevLast == '\'') {

if _, err := w.Write([]byte("\n")); err != nil {

return err

}

} else if whitespaceQueued && (prev != js.StringToken && prev != js.PunctuatorToken && tt != js.PunctuatorToken || first == prevLast && (prevLast == '+' || prevLast == '-')) {

if _, err := w.Write([]byte(" ")); err != nil {

return err

}

}

}

lineTerminatorQueued = false

whitespaceQueued = false

prev = tt

prevLast = text[len(text)-1]

}

if _, err := w.Write(text); err != nil {

return err

}

}

}