Testing ES6 and Otto

es6.go

package main

import (
	"flag"
	"fmt"
	"io/ioutil"
	"log"
	"os"
	"path/filepath"
	"strings"

	"github.com/PuerkitoBio/goquery"
	"github.com/robertkrimen/otto/ast"
	"github.com/robertkrimen/otto/parser"
)

var (
	filename string
	dirname  string
)

func init() {
	flag.StringVar(&filename, "src", "", "path to source file")
	flag.StringVar(&dirname, "dir", "", "path to directory of source files")
}

func dirSrcBlocks(dirname string) []string {
	var blocks []string

	err := filepath.Walk(dirname, func(path string, info os.FileInfo, err error) error {
		if err != nil {
			return err
		}

		if info.IsDir() {
			return nil
		}

		if !strings.HasSuffix(path, ".vue") && !strings.HasSuffix(path, ".html") && !strings.HasSuffix(path, ".js") {
			return nil
		}

		fileBlocks := getSrcBlocks(path)
		blocks = append(blocks, fileBlocks...)
		return nil
	})

	if err != nil {
		log.Fatalln("walk dir:", err)
	}

	return blocks
}

func getSrcBlocks(filename string) []string {
	if !strings.HasSuffix(filename, ".vue") && !strings.HasSuffix(filename, ".html") {
		sourceBytes, err := ioutil.ReadFile(filename)
		if err != nil {
			log.Fatalln("read JS source file:", err)
		}

		return []string{string(sourceBytes)}
	}

	file, err := os.Open(filename)
	if err != nil {
		log.Fatalln("open html/vue file:", err)
	}
	defer file.Close()

	doc, err := goquery.NewDocumentFromReader(file)
	if err != nil {
		log.Fatalln("parse html:", err)
	}

	var blocks []string

	doc.Find("script").EachWithBreak(func(i int, s *goquery.Selection) bool {
		blocks = append(blocks, s.Text())
		return true
	})

	return blocks
}

type walker []ast.Node // stack of nodes

func (w *walker) push(n ast.Node) {
	(*w) = append((*w), n)
	fmt.Println("ENTER:", n)
}

func (w *walker) pop(n ast.Node) {
	size := len(*w)
	if size <= 0 {
		panic("pop of empty stack")
	}

	if (*w)[size-1] != n {
		panic("pop of unexpected node, doesn't match current top of stack")
	}

	fmt.Println("LEAVE:", (*w)[size-1])

	(*w)[size-1] = nil
	*w = (*w)[:size-1]
}

func (w *walker) Enter(n ast.Node) ast.Visitor {
	w.push(n)

	// TODO: print new ES6 nodes as we pass by them

	return w
}

func (w *walker) Exit(n ast.Node) {
	w.pop(n)
}

func main() {
	flag.Parse()

	var blocks []string

	if filename != "" {
		blocks = getSrcBlocks(filename)
	} else if dirname != "" {
		blocks = dirSrcBlocks(dirname)
	} else {
		log.Fatalln("Must supply one of ``-src'' or ``-dir''")
	}

	for _, block := range blocks {
		program, err := parser.ParseFile(nil, filename, block, parser.IgnoreRegExpErrors)
		if err != nil {
			log.Fatalln("parse source block:", err)
		}

		ast.Walk(new(walker), program)
	}
}