lancet/docs/structs/field.md

Field

Field is abstract struct field for provide several high level functions

Source:

• https://github.com/duke-git/lancet/blob/main/structs/field.go

Usage:

import (
    "github.com/duke-git/lancet/v2/structs"
)

Index:

• Tag
• Name
• Value
• Kind
• IsEmbedded
• IsExported
• IsZero
• IsSlice

Note：Since Field inherits from Struct, it also has all the methods of 'Struct', as follows:

• ToMap
• Fields
• Field
• IsStruct

Documentation:

Tag

Get a `Tag` of the `Field`, `Tag` is a abstract struct field tag

Signature:

func (f *Field) Tag() *Tag

Example:

package main

import (
	"fmt"
	"github.com/duke-git/lancet/v2/structs"
)

func main() {
	type Parent struct {
		Name string `json:"name,omitempty"`
	}
	p1 := &Parent{"111"}

	s := structs.New(p1)
	n, _ := s.Field("Name")
	tag := n.Tag()

	fmt.Println(tag.Name)
	
	// Output:
	// name
}

Value

Get the `Field` underlying value

Signature:

func (f *Field) Value() any

Example:

package main

import (
	"fmt"
	"github.com/duke-git/lancet/v2/structs"
)

func main() {
	type Parent struct {
		Name string `json:"name,omitempty"`
	}
	p1 := &Parent{"111"}

	s := structs.New(p1)
	n, _ := s.Field("Name")
	
	fmt.Println(n.Value())
	
	// Output: 
	// 111
}

IsEmbedded

Check if the field is an embedded field

Signature:

func (f *Field) IsEmbedded() bool

Example:

package main

import (
	"fmt"
	"github.com/duke-git/lancet/v2/structs"
)

func main() {
	type Parent struct {
		Name string
	}
	type Child struct {
		Parent
		Age int
	}
	c1 := &Child{}
	c1.Name = "111"
	c1.Age = 11

	s := structs.New(c1)
	n, _ := s.Field("Name")
	a, _ := s.Field("Age")
	
	fmt.Println(n.IsEmbedded())
	fmt.Println(a.IsEmbedded())
	
	// Output: 
	// true
	// false
}

IsExported

Check if the field is exported

Signature:

func (f *Field) IsExported() bool

Example:

package main

import (
	"fmt"
	"github.com/duke-git/lancet/v2/structs"
)

func main() {
	type Parent struct {
		Name string
		age  int
	}
	p1 := &Parent{Name: "11", age: 11}
	s := structs.New(p1)
	n, _ := s.Field("Name")
	a, _ := s.Field("age")
	
	fmt.Println(n.IsExported())
	fmt.Println(a.IsExported())
	
	// Output: 
	// true
	// false
}

IsZero

Check if the field is zero value

Signature:

func (f *Field) IsZero() bool

Example:

package main

import (
	"fmt"
	"github.com/duke-git/lancet/v2/structs"
)

func main() {
	type Parent struct {
		Name string
		Age  int
	}
	p1 := &Parent{Age: 11}
	s := structs.New(p1)
	n, _ := s.Field("Name")
	a, _ := s.Field("Age")
	
	fmt.Println(n.IsZero())
	fmt.Println(a.IsZero())
	
	// Output: 
	// true
	// false
}

Name

Get the field name

Signature:

func (f *Field) Name() string

Example:

package main

import (
	"fmt"
	"github.com/duke-git/lancet/v2/structs"
)

func main() {
	type Parent struct {
		Name string
		Age  int
	}
	p1 := &Parent{Age: 11}
	s := structs.New(p1)
	n, _ := s.Field("Name")
	a, _ := s.Field("Age")
	
	fmt.Println(n.Name())
	fmt.Println(a.Name())
	
	// Output: 
	// Name
	// Age
}

Kind

Get the field's kind

Signature:

func (f *Field) Kind() reflect.Kind

Example:

package main

import (
	"fmt"
	"github.com/duke-git/lancet/v2/structs"
)

func main() {
	type Parent struct {
		Name string
		Age  int
	}
	p1 := &Parent{Age: 11}
	s := structs.New(p1)
	n, _ := s.Field("Name")
	a, _ := s.Field("Age")
	
	fmt.Println(n.Kind())
	fmt.Println(a.Kind())
	
	// Output: 
	// string
	// int
}

IsSlice

Check if the field is a slice

Signature:

func (f *Field) IsSlice() bool

Example:

package main

import (
	"fmt"
	"github.com/duke-git/lancet/v2/structs"
)

func main() {
	type Parent struct {
		Name string
		arr  []int
	}

	p1 := &Parent{arr: []int{1, 2, 3}}
	s := structs.New(p1)
	a, _ := s.Field("arr")
	
	fmt.Println(a.IsSlice())
	
	// Output: 
	// true
}