refactor: remove list rendering setup from component options and related utility
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This commit is contained in:
Astrian Zheng 2025-05-21 16:00:23 +10:00
parent 3b344af52d
commit 8f6b4a6cd9
Signed by: Astrian
SSH Key Fingerprint: SHA256:rVnhx3DAKjujCwWE13aDl7uV6+9U1MvydLkNRXJrBiA
2 changed files with 0 additions and 429 deletions

View File

@ -140,7 +140,6 @@ export default (options: ComponentOptions) => {
setupArrowFunctionHandler: this._setupArrowFunctionHandler.bind(this), setupArrowFunctionHandler: this._setupArrowFunctionHandler.bind(this),
setupExpressionHandler: this._setupExpressionHandler.bind(this), setupExpressionHandler: this._setupExpressionHandler.bind(this),
setupFunctionCallHandler: this._setupFunctionCallHandler.bind(this), setupFunctionCallHandler: this._setupFunctionCallHandler.bind(this),
setupListRendering: this._setupListRendering.bind(this),
stateToElementsMap: this._stateToElementsMap, stateToElementsMap: this._stateToElementsMap,
textBindings: this._textBindings, textBindings: this._textBindings,
availableFuncs: Object.getOwnPropertyNames( availableFuncs: Object.getOwnPropertyNames(
@ -189,433 +188,6 @@ export default (options: ComponentOptions) => {
} }
} }
// Handle list rendering (%for macro)
private _setupListRendering(element: Element, expr: string) {
// Parse the expression (e.g., "item in items" or "(item, index) in items")
const match = expr.match(
/(?:\(([^,]+),\s*([^)]+)\)|([^,\s]+))\s+in\s+(.+)/,
)
if (!match) {
console.error(`Invalid %for expression: ${expr}`)
return
}
// Extract the item variable name, index variable name (optional), and collection expression
const itemVar = match[3] || match[1]
const indexVar = match[2] || null
const collectionExpr = match[4].trim()
// Create a placeholder comment to mark where the list should be rendered
const placeholder = document.createComment(` %for: ${expr} `)
element.parentNode?.insertBefore(placeholder, element)
// Remove the original template element from the DOM
const template = element.cloneNode(true) as Element
element.parentNode?.removeChild(element)
// Store current rendered items
const renderedItems: Array<{
element: Element
key: unknown
data: unknown
index: number
}> = []
// Create a function to update the list when the collection changes
const updateList = () => {
const collection = this._evaluateExpression(collectionExpr)
if (!collection || !Array.isArray(collection)) {
console.warn(
`Collection "${collectionExpr}" is not an array or does not exist`,
)
return
}
const parentNode = placeholder.parentNode
if (!parentNode) {
console.error("Placeholder's parentNode is null. Cannot update list.")
return
}
// Detach all currently rendered DOM items managed by this instance.
for (const item of renderedItems)
if (item.element.parentNode === parentNode)
parentNode.removeChild(item.element)
// Get key attribute if available
const keyAttr = template.getAttribute('%key')
if (!keyAttr)
console.warn(
'%key attribute not found in the template, which is not a recommended practice.',
)
// Store a map of existing items by key for reuse
const existingElementsByKey = new Map()
// renderedItems.forEach((item) => {
for (const item of renderedItems)
if (item.key !== undefined) existingElementsByKey.set(item.key, item)
// Clear rendered items
renderedItems.length = 0
// document fragment
const fragment = document.createDocumentFragment()
// Create or update items in the list
collection.forEach((item, index) => {
// Determine the key for this item
const key = keyAttr
? this._evaluateExpressionWithItemContext(
keyAttr ?? '',
item,
index,
itemVar,
indexVar ? indexVar : undefined,
)
: index
// Check if we can reuse an existing element
const existingItem = existingElementsByKey.get(key)
let itemElement: Element
if (existingItem) {
// Reuse existing element
itemElement = existingItem.element
existingElementsByKey.delete(key) // Remove from map so we know it's been used
} else {
// Create a new element
itemElement = template.cloneNode(true) as Element
}
// Update item data
renderedItems.push({
element: itemElement,
key,
data: item,
index,
})
// Create item context for this item
const itemContext = {
[itemVar]: item,
}
if (indexVar) itemContext[indexVar] = index
// insert %key attribute, which dynamically bind the key
if (keyAttr) {
const keyValue = this._evaluateExpressionWithItemContext(
keyAttr,
itemContext,
)
itemElement.setAttribute('data-laterano-key', String(keyValue))
}
// remove original %key attribute
itemElement.removeAttribute('%key')
// Apply the item context to the element
// We will use recursive processing here!
this._processElementWithItemContext(itemElement, itemContext)
// Insert the element to the document fragment
fragment.appendChild(itemElement)
})
// Insert the document fragment into the DOM
placeholder.parentNode?.insertBefore(fragment, placeholder.nextSibling)
// Remove any remaining unused items
// existingElementsByKey.forEach((item) => {
for (const item of existingElementsByKey.values())
if (item.element.parentNode)
item.element.parentNode.removeChild(item.element)
}
// Initial render
updateList()
// Set up state dependency for collection changes
if (!this._stateToElementsMap[collectionExpr])
this._stateToElementsMap[collectionExpr] = new Set()
// Using a unique identifier for this list rendering instance
const listVirtualElement = document.createElement('div')
this._stateToElementsMap[collectionExpr].add(
listVirtualElement as HTMLElement,
)
// Add listener for state changes
this._statesListeners[collectionExpr] = () => {
updateList()
}
}
// Recursively process the element and its children, applying the item context
private _processElementWithItemContext(
element: Element,
itemContext: Record<string, unknown>,
) {
// 1. Store the item context of the element so that subsequent updates can find it
;(element as { _itemContext?: Record<string, unknown> })._itemContext =
itemContext
// 2. Process bindings in text nodes
const processTextNodes = (node: Node) => {
if (node.nodeType === Node.TEXT_NODE) {
const textContent = node.textContent || ''
if (textContent.includes('{{')) {
const textNode = node as Text
const updatedContent = textContent.replace(
/\{\{\s*([^}]+)\s*\}\}/g,
(match, expr) => {
const value = this._evaluateExpressionWithItemContext(
expr.trim(),
itemContext,
)
return value !== undefined ? String(value) : ''
},
)
textNode.textContent = updatedContent
}
}
}
// Process the text nodes of the element itself
// Array.from(element.childNodes).forEach((node) => {
for (const node of Array.from(element.childNodes))
if (node.nodeType === Node.TEXT_NODE) processTextNodes(node)
// 3. Process attribute bindings (:attr)
// Array.from(element.attributes).forEach((attr) => {
for (const attr of Array.from(element.attributes)) {
if (attr.name.startsWith(':')) {
const attrName = attr.name.substring(1)
const expr = attr.value.trim()
const value = this._evaluateExpressionWithItemContext(
expr,
itemContext,
)
if (value !== undefined) element.setAttribute(attrName, String(value))
// Remove the original binding attribute (execute only for cloned templates once)
element.removeAttribute(attr.name)
}
}
// 4. Process event bindings (@event)
// Array.from(element.attributes).forEach((attr) => {
for (const attr of Array.from(element.attributes)) {
if (attr.name.startsWith('@')) {
const eventName = attr.name.substring(1)
const handlerValue = attr.value.trim()
// Remove the original binding attribute
element.removeAttribute(attr.name)
// Add event listener
element.addEventListener(eventName, (event: Event) => {
try {
// Create a merged context
const mergedContext = {
...this._createHandlerContext(event, element),
...itemContext,
$event: event,
$el: element,
}
// Execute the expression
const fnStr = `with(this) { ${handlerValue} }`
new Function(fnStr).call(mergedContext)
} catch (err) {
console.error(
`Error executing event handler with item context: ${handlerValue}`,
err,
)
}
})
}
}
// 5. Process conditional rendering (%if)
let isConditional = false
let shouldDisplay = true
// Array.from(element.attributes).forEach((attr) => {
for (const attr of Array.from(element.attributes)) {
if (attr.name === '%if') {
isConditional = true
const expr = attr.value.trim()
// Remove the original binding attribute
element.removeAttribute(attr.name)
// Calculate the condition
const result = this._evaluateExpressionWithItemContext(
expr,
itemContext,
)
shouldDisplay = Boolean(result)
// Apply the condition (in the list item context, we use display style to simplify)
if (!shouldDisplay) (element as HTMLElement).style.display = 'none'
}
}
// If the condition evaluates to false, skip further processing of this element
if (isConditional && !shouldDisplay) {
return
}
// 6. Process nested list rendering (%for)
let hasForDirective = false
// Array.from(element.attributes).forEach((attr) => {
for (const attr of Array.from(element.attributes)) {
if (attr.name === '%for') {
hasForDirective = true
const forExpr = attr.value.trim()
// Remove the original binding attribute
element.removeAttribute(attr.name)
// Here we will create a new nested list
// Note: We need to evaluate the collection expression through the current item context here
this._setupNestedListRendering(element, forExpr, itemContext)
}
}
// If this element is a list element, skip child element processing (they will be processed by the list processor)
if (hasForDirective) return
// 7. Recursively process all child elements
// Array.from(element.children).forEach((child) => {
for (const child of Array.from(element.children))
this._processElementWithItemContext(child, itemContext)
}
// Set up nested list rendering
private _setupNestedListRendering(
element: Element,
expr: string,
parentItemContext: Record<string, unknown>,
) {
// Similar to _setupListRendering, but applies to nested situations
// Parse the expression (e.g., "subItem in item.subItems")
const match = expr.match(
/(?:\(([^,]+),\s*([^)]+)\)|([^,\s]+))\s+in\s+(.+)/,
)
if (!match) {
console.error(`Invalid nested %for expression: ${expr}`)
return
}
// Extract the item variable name, index variable name (optional), and collection expression
const itemVar = match[3] || match[1]
const indexVar = match[2] || null
const collectionExpr = match[4].trim()
// Evaluate the collection expression, using the parent item context
const collection = this._evaluateExpressionWithItemContext(
collectionExpr,
parentItemContext,
)
if (!collection || !Array.isArray(collection)) {
console.warn(
`Nested collection "${collectionExpr}" is not an array or does not exist`,
)
return
}
// Create a placeholder comment
const placeholder = document.createComment(` %for: ${expr} `)
element.parentNode?.insertBefore(placeholder, element)
// Remove the original template element from the DOM
const template = element.cloneNode(true) as Element
element.parentNode?.removeChild(element)
// Create an element for each item
collection.forEach((item, index) => {
const itemElement = template.cloneNode(true) as Element
// Create a nested item context, merging the parent context
const nestedItemContext = {
...parentItemContext,
[itemVar]: item,
}
if (indexVar) {
nestedItemContext[indexVar] = index
}
// Recursively process this item and its children
this._processElementWithItemContext(itemElement, nestedItemContext)
// TODO: detect list items existed inside the view, use replace instead of remove and re-add,
// to improve performance
// Insert the item element into the DOM
placeholder.parentNode?.insertBefore(
itemElement,
placeholder.nextSibling,
)
})
}
// Evaluate expressions using the item context
private _evaluateExpressionWithItemContext(
expression: string,
itemContext: Record<string, unknown>,
index?: number,
itemVar?: string,
indexVar?: string,
): unknown {
try {
// Check if the expression directly references the item variable
if (itemVar && expression === itemVar) {
return itemContext[itemVar]
}
// Check if the expression is an item property path
if (itemVar && expression.startsWith(`${itemVar}.`)) {
const propertyPath = expression.substring(itemVar.length + 1)
const parts = propertyPath.split('.')
let value = itemContext[itemVar]
for (const part of parts) {
if (value === undefined || value === null) return undefined
value = (value as { [key: string]: unknown })[part]
}
return value
}
// Check if the expression directly references the index variable
if (indexVar && expression === indexVar) {
return index
}
// Create a merged context (component state + item context)
const mergedContext = { ...this._states, ...itemContext }
// Create a function to evaluate the expression
const contextKeys = Object.keys(mergedContext)
const contextValues = Object.values(mergedContext)
// Use the with statement to allow the expression to access all properties in the context
const func = new Function(...contextKeys, `return ${expression}`)
return func(...contextValues)
} catch (error) {
console.error(
`Error evaluating expression with item context: ${expression}`,
error,
)
return undefined
}
}
private _evaluateIfCondition(element: Element, condition: string) { private _evaluateIfCondition(element: Element, condition: string) {
const info = this._conditionalElements.get(element) const info = this._conditionalElements.get(element)
if (!info) return if (!info) return

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@ -24,7 +24,6 @@ export default function processTemplateMacros(
eventName: string, eventName: string,
handlerValue: string, handlerValue: string,
) => void ) => void
setupListRendering: (element: Element, expr: string) => void
stateToElementsMap: Record<string, Set<HTMLElement>> stateToElementsMap: Record<string, Set<HTMLElement>>
textBindings: { textBindings: {
node: Text node: Text