typeconv

README

go-typeconv

Safe type conversion utilities for Go. Handle interface{} values from JSON, configs, and APIs.

Installation

go get github.com/philiprehberger/go-typeconv

Usage

Type Conversions

import "github.com/philiprehberger/go-typeconv"

// Working with JSON-decoded data
data := map[string]any{
    "port":    8080.0,
    "debug":   "true",
    "timeout": "30s",
}

port, err := typeconv.ToInt(data["port"])       // 8080, nil
debug, err := typeconv.ToBool(data["debug"])    // true, nil
timeout, err := typeconv.ToDuration(data["timeout"]) // 30s, nil

Pointer Helpers

// Create pointers to literals
name := typeconv.Ptr("Alice")   // *string

// Safe dereference with fallback
val := typeconv.Deref(name, "unknown")   // "Alice"
val = typeconv.Deref((*string)(nil), "unknown") // "unknown"

// Safe dereference with zero value
val = typeconv.DerefOrZero((*string)(nil)) // ""

Must Variants

// When you know the conversion will succeed
port := typeconv.MustInt("8080") // 8080
// Panics on failure — use only when input is trusted

API

Function	Description
ToInt(v any) (int, error)	Convert to int from int/float/string/bool
ToInt64(v any) (int64, error)	Convert to int64
ToFloat64(v any) (float64, error)	Convert to float64 from numeric/string
ToString(v any) (string, error)	Convert to string from string/[]byte/Stringer/numeric
ToBool(v any) (bool, error)	Convert to bool from bool/string/int
ToDuration(v any) (time.Duration, error)	Convert to Duration from Duration/string/int64
ToStringSlice(v any) ([]string, error)	Convert to []string from []string/[]any
MustInt(v any) int	ToInt or panic
MustInt64(v any) int64	ToInt64 or panic
MustFloat64(v any) float64	ToFloat64 or panic
MustString(v any) string	ToString or panic
MustBool(v any) bool	ToBool or panic
MustDuration(v any) time.Duration	ToDuration or panic
Ptr[T any](v T) *T	Return pointer to value
Deref[T any](p *T, fallback T) T	Dereference or fallback
DerefOrZero[T any](p *T) T	Dereference or zero value

License

MIT

Documentation

Overview

Package typeconv provides safe type conversion utilities for Go.

It handles interface{} values commonly encountered when working with JSON, configuration files, and external APIs, converting them to concrete Go types with clear error messages for unsupported conversions.

Index

• func Deref[T any](p *T, fallback T) T
• func DerefOrZero[T any](p *T) T
• func MustBool(v any) bool
• func MustDuration(v any) time.Duration
• func MustFloat64(v any) float64
• func MustInt(v any) int
• func MustInt64(v any) int64
• func MustString(v any) string
• func Ptr[T any](v T) *T
• func ToBool(v any) (bool, error)
• func ToDuration(v any) (time.Duration, error)
• func ToFloat64(v any) (float64, error)
• func ToInt(v any) (int, error)
• func ToInt64(v any) (int64, error)
• func ToString(v any) (string, error)
• func ToStringSlice(v any) ([]string, error)

Functions

func Deref

func Deref[T any](p *T, fallback T) T

Deref dereferences a pointer, returning the pointed-to value. If the pointer is nil, it returns the provided fallback value.

func DerefOrZero

func DerefOrZero[T any](p *T) T

DerefOrZero dereferences a pointer, returning the pointed-to value. If the pointer is nil, it returns the zero value for the type.

func MustBool

func MustBool(v any) bool

MustBool converts a value to bool, panicking if the conversion fails.

func MustDuration

func MustDuration(v any) time.Duration

MustDuration converts a value to time.Duration, panicking if the conversion fails.

func MustFloat64

func MustFloat64(v any) float64

MustFloat64 converts a value to float64, panicking if the conversion fails.

func MustInt

func MustInt(v any) int

MustInt converts a value to int, panicking if the conversion fails.

func MustInt64

func MustInt64(v any) int64

MustInt64 converts a value to int64, panicking if the conversion fails.

func MustString

func MustString(v any) string

MustString converts a value to string, panicking if the conversion fails.

func Ptr

func Ptr[T any](v T) *T

Ptr returns a pointer to the given value. This is useful for creating pointers to literals or inline values.

func ToBool

func ToBool(v any) (bool, error)

ToBool converts a value to bool. Supported source types:

• bool (pass through)
• string ("true", "false", "1", "0", "yes", "no" — case insensitive)
• int, int8, int16, int32, int64 (0=false, nonzero=true)
• uint, uint8, uint16, uint32, uint64 (0=false, nonzero=true)

func ToDuration

func ToDuration(v any) (time.Duration, error)

ToDuration converts a value to time.Duration. Supported source types:

• time.Duration (pass through)
• string (parsed via time.ParseDuration, e.g. "30s", "5m", "1h30m")
• int64 (interpreted as nanoseconds)

func ToFloat64

func ToFloat64(v any) (float64, error)

ToFloat64 converts a value to float64. Supported source types:

• int, int8, int16, int32, int64
• uint, uint8, uint16, uint32, uint64
• float32, float64
• string (parsed via strconv.ParseFloat)

func ToInt

func ToInt(v any) (int, error)

ToInt converts a value to int. Supported source types:

• int, int8, int16, int32, int64
• uint, uint8, uint16, uint32, uint64
• float32, float64 (only if the value has no fractional part)
• string (parsed via strconv.Atoi)
• bool (true=1, false=0)

func ToInt64

func ToInt64(v any) (int64, error)

ToInt64 converts a value to int64. Supported source types:

• int, int8, int16, int32, int64
• uint, uint8, uint16, uint32, uint64
• float32, float64 (only if the value has no fractional part)
• string (parsed via strconv.ParseInt)
• bool (true=1, false=0)

func ToString

func ToString(v any) (string, error)

ToString converts a value to string. Supported source types:

• string (pass through)
• []byte
• fmt.Stringer (calls String())
• numeric types and bool (via fmt.Sprint)

func ToStringSlice

func ToStringSlice(v any) ([]string, error)

ToStringSlice converts a value to []string. Supported source types:

• []string (pass through)
• []any (each element is converted via ToString)