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