add JavaScript deps parser

packer/deps.go

@@ -0,0 +1,53 @@
+package packer
+
+import (
+	"bufio"
+	"fmt"
+	"os"
+	"path/filepath"
+	"regexp"
+	"strings"
+)
+
+// JavaScriptExt extension of JavaScript source file
+const JavaScriptExt = ".js"
+
+func depsJavaScript(src string) ([]string, error) {
+	deps := []string{}
+	file, err := os.Open(src)
+	if err != nil {
+		return nil, err
+	}
+	defer file.Close()
+
+	scanner := bufio.NewScanner(file)
+	for scanner.Scan() {
+		line := strings.TrimSpace(scanner.Text())
+		if strings.HasPrefix(line, "import") || strings.HasPrefix(line, "require") {
+			reg, err := regexp.Compile(`(\'.*\'|\".*\")`)
+			if err != nil {
+				return nil, err
+			}
+			str := reg.FindString(line)
+			if str != "" {
+				deps = append(deps, strings.ReplaceAll(strings.ReplaceAll(str, "\"", ""), "'", ""))
+			}
+		}
+	}
+
+	if err := scanner.Err(); err != nil {
+		return nil, err
+	}
+	return deps, nil
+}
+
+// Deps to get the dependencies required from a source code in a file
+func Deps(src string) ([]string, error) {
+	switch filepath.Ext(src) {
+	case JavaScriptExt:
+		{
+			return depsJavaScript(src)
+		}
+	}
+	return nil, fmt.Errorf("not support language: %s", filepath.Ext(src))
+}

packer/deps_test.go

@@ -0,0 +1,63 @@
+package packer
+
+import (
+	"io/ioutil"
+	"os"
+	"reflect"
+	"testing"
+)
+
+func TestDeps(t *testing.T) {
+	cases := []struct {
+		name    string
+		content string
+		expect  []string
+	}{
+		{name: "import with singe quote", content: "import 'pkg1'", expect: []string{"pkg1"}},
+		{name: "import with double quote", content: `import "pkg1"`, expect: []string{"pkg1"}},
+		{name: "require with singe quote", content: "require 'pkg1'", expect: []string{"pkg1"}},
+		{name: "require with double quote", content: `require "pkg1"`, expect: []string{"pkg1"}},
+		{
+			name: "require and import with singe quote",
+			content: `
+require 'pkg1'
+import 'pkg2'`,
+			expect: []string{"pkg1", "pkg2"},
+		},
+		{
+			name: "require and import with double quote",
+			content: `
+require "pkg1"
+import "pkg2"`,
+			expect: []string{"pkg1", "pkg2"},
+		},
+		{
+			name: "require and import with double quote and single quote",
+			content: `
+require 'pkg1'
+import "pkg2"`,
+			expect: []string{"pkg1", "pkg2"},
+		},
+	}
+
+	for _, c := range cases {
+		fd, err := ioutil.TempFile("", "dep_pkg_*.js")
+		if err != nil {
+			t.Fatal(err)
+		}
+		defer os.Remove(fd.Name())
+
+		err = ioutil.WriteFile(fd.Name(), []byte(c.content), 0666)
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		deps, err := Deps(fd.Name())
+		if err != nil {
+			t.Fatal(err)
+		}
+		if !reflect.DeepEqual(deps, c.expect) {
+			t.Fatalf("%s: should get %s but got %s", c.name, c.expect, deps)
+		}
+	}
+}