pkg/

GoPCA Shared Packages

This directory contains shared backend packages used by both GoPCA and GoCSV applications. These packages implement common functionality to ensure consistency and reduce code duplication.

Note: For shared frontend components (React/TypeScript), see packages/ui-components/

Package Structure

pkg/types/

Core types and data structures shared across applications.

• json.go: Provides JSONFloat64 type for safe JSON marshaling of special float values (NaN, Inf)
  • Marshals NaN and Inf as null for JavaScript compatibility
  • Unmarshals null as NaN
  • Includes helper methods: Float64(), IsNaN(), IsInf()

pkg/utils/

Common utility functions for data processing.

• missing.go: Missing value detection and handling

  • DefaultMissingValues(): Returns standard missing value indicators
  • IsMissingValue(): Checks if a string represents missing data
  • ContainsMissingValues(): Checks if a slice contains missing values
  • CountMissingValues(): Counts missing values in a slice

• parsing.go: Numeric parsing utilities

  • ParseNumericValue(): Parses strings to float64 with decimal separator support
  • ParseNumericValueWithMissing(): Combines parsing with missing value detection
  • IsNumericString(): Checks if a string can be parsed as a number
  • ParseFloatSlice(): Parses a slice of strings to float64 values

Usage Examples

JSON-Safe Float Handling

import "github.com/bitjungle/gopca/pkg/types"

// Create a JSON-safe float
value := types.JSONFloat64(math.NaN())

// Marshal to JSON (becomes "null")
data, _ := json.Marshal(value)

// Check if value is NaN
if value.IsNaN() {
    // Handle NaN case
}

Missing Value Detection

import "github.com/bitjungle/gopca/pkg/utils"

// Use default missing indicators
missingIndicators := utils.DefaultMissingValues()

// Check if a value is missing
if utils.IsMissingValue("NA", missingIndicators) {
    // Handle missing value
}

// Count missing values in data
count := utils.CountMissingValues(dataSlice, missingIndicators)

Numeric Parsing

import "github.com/bitjungle/gopca/pkg/utils"

// Parse with decimal separator
value, err := utils.ParseNumericValue("123,45", ',')

// Parse with missing value detection
val, isMissing, err := utils.ParseNumericValueWithMissing(
    "NA", '.', utils.DefaultMissingValues())
if isMissing {
    // Value is missing (val = NaN)
}

Design Principles

1. Consistency: Both applications handle data the same way
2. Robustness: Comprehensive error handling and edge case coverage
3. Performance: Efficient implementations with benchmarks
4. Testability: High test coverage (>90%) with table-driven tests
5. Simplicity: Clear, single-purpose functions following KISS principle

Testing

Run tests for shared packages:

go test ./pkg/...

Run with coverage:

go test -cover ./pkg/...

Contributing

When modifying shared packages:

1. Ensure changes don't break existing functionality
2. Add comprehensive tests for new features
3. Update documentation as needed
4. Test both GoPCA and GoCSV after changes
5. Follow the project's coding standards from CLAUDE.md