feat: javascript code parser for transformations

cli/internal/providers/transformations/parser/javascript.go

@@ -0,0 +1,179 @@
+package parser
+
+import (
+	"fmt"
+	"regexp"
+	"strings"
+
+	"github.com/evanw/esbuild/pkg/api"
+)
+
+// JavaScriptParser extracts imports from JavaScript code using esbuild
+type JavaScriptParser struct{}
+
+// ValidateSyntax validates JavaScript code syntax using esbuild
+func (p *JavaScriptParser) ValidateSyntax(code string) error {
+	result := api.Transform(code, api.TransformOptions{
+		Loader: api.LoaderJS,
+	})
+
+	if len(result.Errors) > 0 {
+		// Collect all error messages
+		var errorMsgs []string
+		for _, err := range result.Errors {
+			errorMsgs = append(errorMsgs, err.Text)
+		}
+		return fmt.Errorf("javascript syntax error: %s", strings.Join(errorMsgs, "; "))
+	}
+
+	return nil
+}
+
+// ExtractImports parses JavaScript code and returns external library import names.
+// Returns an error if the code contains:
+// - require() syntax (CommonJS not supported)
+// - Relative imports (./file, ../file)
+// - Absolute imports (/path)
+// Filters out RudderStack built-in libraries (@rs/<library>/<version>)
+func (p *JavaScriptParser) ExtractImports(code string) ([]string, error) {
+	result := api.Transform(code, api.TransformOptions{
+		Loader: api.LoaderJS,
+		Format: api.FormatESModule,
+	})
+
+	if len(result.Errors) > 0 {
+		var errorMsgs []string
+		for _, err := range result.Errors {
+			errorMsgs = append(errorMsgs, err.Text)
+		}
+		return nil, fmt.Errorf("extracting imports: %s", strings.Join(errorMsgs, "; "))
+	}
+
+	transformedCode := string(result.Code)
+
+	// Validate no require() in transformed code
+	if err := validateNoRequire(transformedCode); err != nil {
+		return nil, err
+	}
+
+	// Extract all import statements
+	imports := extractAllImports(transformedCode)
+
+	// Validate and filter imports
+	libraryImports := make([]string, 0)
+	for imp := range imports {
+		if isRelativeOrAbsoluteImport(imp) {
+			return nil, fmt.Errorf("relative imports (./file, ../file) and absolute imports (/path) are not supported")
+		}
+		if isExternalLibraryImport(imp) {
+			libraryImports = append(libraryImports, imp)
+		}
+	}
+
+	return libraryImports, nil
+}
+
+// validateNoRequire checks if transformed code contains require() calls
+func validateNoRequire(code string) error {
+	i := 0
+	for i < len(code) {
+		idx := strings.Index(code[i:], "require")
+		if idx == -1 {
+			break
+		}
+
+		pos := i + idx
+		i = pos + 7 // Move past "require"
+
+		// Check if followed by ( with optional whitespace
+		for j := pos + 7; j < len(code); j++ {
+			ch := code[j]
+			if ch == ' ' || ch == '\t' || ch == '\n' {
+				continue
+			}
+			if ch == '(' {
+				return fmt.Errorf("require() syntax is not supported")
+			}
+			break
+		}
+	}
+	return nil
+}
+
+// extractAllImports extracts all import paths from esbuild-transformed code
+func extractAllImports(code string) map[string]bool {
+	imports := make(map[string]bool)
+
+	i := 0
+	for i < len(code) {
+		idx := strings.Index(code[i:], "import")
+		if idx == -1 {
+			break
+		}
+
+		pos := i + idx
+		i = pos + 1
+
+		// Extract module name from import statement
+		remaining := code[pos+6:] // Skip "import"
+
+		// Look for "from" keyword
+		fromIdx := strings.Index(remaining, "from")
+		if fromIdx != -1 {
+			remaining = remaining[fromIdx+4:]
+		}
+
+		if moduleName := extractQuotedString(remaining); moduleName != "" {
+			imports[moduleName] = true
+		}
+	}
+
+	return imports
+}
+
+// extractQuotedString extracts the first quoted string from text
+func extractQuotedString(text string) string {
+	// Skip whitespace and opening parenthesis
+	start := 0
+	for start < len(text) && (text[start] == ' ' || text[start] == '\t' || text[start] == '\n' || text[start] == '(') {
+		start++
+	}
+
+	if start >= len(text) {
+		return ""
+	}
+
+	// Find opening quote
+	quote := text[start]
+	if quote != '"' && quote != '\'' && quote != '`' {
+		return ""
+	}
+
+	// Find closing quote
+	for i := start + 1; i < len(text); i++ {
+		if text[i] == quote {
+			return text[start+1 : i]
+		}
+	}
+
+	return ""
+}
+
+// isRelativeOrAbsoluteImport checks if import is relative (./file, ../file) or absolute (/path)
+func isRelativeOrAbsoluteImport(path string) bool {
+	return strings.HasPrefix(path, "./") || strings.HasPrefix(path, "../") || strings.HasPrefix(path, "/")
+}
+
+// rudderStackLibraryPattern matches RudderStack built-in library imports
+// Pattern: @rs/<library>/v<digits>
+// Examples: @rs/hash/v1, @rs/utils/v2, @rs/crypto/v10
+var rudderStackLibraryPattern = regexp.MustCompile(`^@rs/[^/]+/v\d+$`)
+
+func isRudderStackLibrary(path string) bool {
+	return rudderStackLibraryPattern.MatchString(path)
+}
+
+// isExternalLibraryImport checks if import is an external library (not RudderStack built-in)
+func isExternalLibraryImport(path string) bool {
+	return path != "" && !isRudderStackLibrary(path)
+}