trackby

README

TrackBy Test Components

This directory tests both formats of the trackBy clause:

1. Bare Variable - For primitive types (string, int, etc.)
2. Dot-Notation - For struct fields (user.ID, etc.)

Components

TagList

Tests bare variable trackBy with a slice of primitive strings:

type TagList struct {
    Tags []string  // Slice of primitive strings
}

Template:

{@for _, tag := range Tags trackBy tag}
    <li>Tag: {tag}</li>
{@endfor}

ProductList

Tests dot-notation trackBy with a slice of structs:

type Product struct {
    ID   int
    Name string
}

type ProductList struct {
    Products []Product  // Slice of structs
}

Template:

{@for _, product := range Products trackBy product.ID}
    <li>Product: {product.Name}</li>
{@endfor}

Building

Both test components can be compiled together:

cd compiler
go run . -in ../testcomponents/trackby

Expected output:

🎉 Compilation completed successfully!

Both trackBy formats compile without errors and generate proper Render() methods.

Key Differences

Feature	Bare Variable	Dot-Notation
Use Case	Primitive types (string, int, bool)	Struct fields
Syntax	trackBy varName	trackBy varName.Field
Example	trackBy tag	trackBy product.ID
Validation	Validates match with loop variable	Validates field exists on struct type

Documentation

Index

• type Item
• type MultiItemList
  • func (m *MultiItemList) AddItem(name string)
  • func (m *MultiItemList) ClearItems()
  • func (m *MultiItemList) OnMount()
• type Product
• type ProductList
  • func (p *ProductList) AddProduct(name string)
  • func (p *ProductList) ClearProducts()
  • func (p *ProductList) OnMount()
• type TagList
  • func (t *TagList) AddTag(newTag string)
  • func (t *TagList) ClearTags()
  • func (t *TagList) OnMount()

Types

type Item

type Item struct {
	ID   int
	Name string
}

Item represents a data item with ID for trackBy

type MultiItemList

type MultiItemList struct {
	runtime.ComponentBase
	Items []Item
}

MultiItemList demonstrates trackBy with multiple sibling child elements per loop iteration. This tests a critical compiler edge case where multiple children in a loop body previously caused variable shadowing errors.

func (*MultiItemList) AddItem

func (m *MultiItemList) AddItem(name string)

func (*MultiItemList) ClearItems

func (m *MultiItemList) ClearItems()

func (*MultiItemList) OnMount

func (m *MultiItemList) OnMount()

type Product

type Product struct {
	ID   int
	Name string
}

Product represents an item with an ID for trackBy

type ProductList

type ProductList struct {
	runtime.ComponentBase
	Products []Product
}

ProductList demonstrates trackBy with struct slice using dot-notation

func (*ProductList) AddProduct

func (p *ProductList) AddProduct(name string)

func (*ProductList) ClearProducts

func (p *ProductList) ClearProducts()

func (*ProductList) OnMount

func (p *ProductList) OnMount()

type TagList

type TagList struct {
	runtime.ComponentBase
	Tags []string
}

TagList demonstrates trackBy with primitive string slice

func (*TagList) AddTag

func (t *TagList) AddTag(newTag string)

func (*TagList) ClearTags

func (t *TagList) ClearTags()

func (*TagList) OnMount

func (t *TagList) OnMount()