vue3-yuanma/packages/compiler-core/src/transforms/vSlot.ts

329 lines
9.7 KiB
TypeScript

import {
ElementNode,
ObjectExpression,
createObjectExpression,
NodeTypes,
createObjectProperty,
createSimpleExpression,
createFunctionExpression,
DirectiveNode,
ElementTypes,
ExpressionNode,
Property,
TemplateChildNode,
SourceLocation,
createConditionalExpression,
ConditionalExpression,
JSChildNode,
SimpleExpressionNode,
FunctionExpression,
CallExpression,
createCallExpression,
createArrayExpression
} from '../ast'
import { TransformContext, NodeTransform } from '../transform'
import { createCompilerError, ErrorCodes } from '../errors'
import { findDir, isTemplateNode, assert, isVSlot } from '../utils'
import { CREATE_SLOTS, RENDER_LIST } from '../runtimeHelpers'
import { parseForExpression, createForLoopParams } from './vFor'
const isStaticExp = (p: JSChildNode): p is SimpleExpressionNode =>
p.type === NodeTypes.SIMPLE_EXPRESSION && p.isStatic
const defaultFallback = createSimpleExpression(`undefined`, false)
// A NodeTransform that:
// 1. Tracks scope identifiers for scoped slots so that they don't get prefixed
// by transformExpression. This is only applied in non-browser builds with
// { prefixIdentifiers: true }.
// 2. Track v-slot depths so that we know a slot is inside another slot.
// Note the exit callback is executed before buildSlots() on the same node,
// so only nested slots see positive numbers.
export const trackSlotScopes: NodeTransform = (node, context) => {
if (
node.type === NodeTypes.ELEMENT &&
(node.tagType === ElementTypes.COMPONENT ||
node.tagType === ElementTypes.TEMPLATE)
) {
// We are only checking non-empty v-slot here
// since we only care about slots that introduce scope variables.
const vSlot = findDir(node, 'slot')
if (vSlot) {
const slotProps = vSlot.exp
if (!__BROWSER__ && context.prefixIdentifiers) {
slotProps && context.addIdentifiers(slotProps)
}
context.scopes.vSlot++
return () => {
if (!__BROWSER__ && context.prefixIdentifiers) {
slotProps && context.removeIdentifiers(slotProps)
}
context.scopes.vSlot--
}
}
}
}
// A NodeTransform that tracks scope identifiers for scoped slots with v-for.
// This transform is only applied in non-browser builds with { prefixIdentifiers: true }
export const trackVForSlotScopes: NodeTransform = (node, context) => {
let vFor
if (
isTemplateNode(node) &&
node.props.some(isVSlot) &&
(vFor = findDir(node, 'for'))
) {
const result = (vFor.parseResult = parseForExpression(
vFor.exp as SimpleExpressionNode,
context
))
if (result) {
const { value, key, index } = result
const { addIdentifiers, removeIdentifiers } = context
value && addIdentifiers(value)
key && addIdentifiers(key)
index && addIdentifiers(index)
return () => {
value && removeIdentifiers(value)
key && removeIdentifiers(key)
index && removeIdentifiers(index)
}
}
}
}
// Instead of being a DirectiveTransform, v-slot processing is called during
// transformElement to build the slots object for a component.
export function buildSlots(
node: ElementNode,
context: TransformContext
): {
slots: ObjectExpression | CallExpression
hasDynamicSlots: boolean
} {
const { children, loc } = node
const slotsProperties: Property[] = []
const dynamicSlots: (ConditionalExpression | CallExpression)[] = []
// If the slot is inside a v-for or another v-slot, force it to be dynamic
// since it likely uses a scope variable.
// TODO: This can be further optimized to only make it dynamic when the slot
// actually uses the scope variables.
let hasDynamicSlots = context.scopes.vSlot > 1 || context.scopes.vFor > 0
// 1. Check for default slot with slotProps on component itself.
// <Comp v-slot="{ prop }"/>
const explicitDefaultSlot = findDir(node, 'slot', true)
if (explicitDefaultSlot) {
const { arg, exp, loc } = explicitDefaultSlot
if (arg) {
context.onError(
createCompilerError(ErrorCodes.X_V_SLOT_NAMED_SLOT_ON_COMPONENT, loc)
)
}
slotsProperties.push(buildDefaultSlot(exp, children, loc))
}
// 2. Iterate through children and check for template slots
// <template v-slot:foo="{ prop }">
let hasTemplateSlots = false
let extraneousChild: TemplateChildNode | undefined = undefined
const seenSlotNames = new Set<string>()
for (let i = 0; i < children.length; i++) {
const slotElement = children[i]
let slotDir
if (
!isTemplateNode(slotElement) ||
!(slotDir = findDir(slotElement, 'slot', true))
) {
// not a <template v-slot>, skip.
if (slotElement.type !== NodeTypes.COMMENT && !extraneousChild) {
extraneousChild = slotElement
}
continue
}
if (explicitDefaultSlot) {
// already has on-component default slot - this is incorrect usage.
context.onError(
createCompilerError(ErrorCodes.X_V_SLOT_MIXED_SLOT_USAGE, slotDir.loc)
)
break
}
hasTemplateSlots = true
const { children: slotChildren, loc: slotLoc } = slotElement
const {
arg: slotName = createSimpleExpression(`default`, true),
exp: slotProps,
loc: dirLoc
} = slotDir
// check if name is dynamic.
let staticSlotName: string | undefined
if (isStaticExp(slotName)) {
staticSlotName = slotName ? slotName.content : `default`
} else {
hasDynamicSlots = true
}
const slotFunction = createFunctionExpression(
slotProps,
slotChildren,
false,
slotChildren.length ? slotChildren[0].loc : slotLoc
)
// check if this slot is conditional (v-if/v-for)
let vIf: DirectiveNode | undefined
let vElse: DirectiveNode | undefined
let vFor: DirectiveNode | undefined
if ((vIf = findDir(slotElement, 'if'))) {
hasDynamicSlots = true
dynamicSlots.push(
createConditionalExpression(
vIf.exp!,
buildDynamicSlot(slotName, slotFunction),
defaultFallback
)
)
} else if (
(vElse = findDir(slotElement, /^else(-if)?$/, true /* allowEmpty */))
) {
// find adjacent v-if
let j = i
let prev
while (j--) {
prev = children[j]
if (prev.type !== NodeTypes.COMMENT) {
break
}
}
if (prev && isTemplateNode(prev) && findDir(prev, 'if')) {
// remove node
children.splice(i, 1)
i--
__DEV__ && assert(dynamicSlots.length > 0)
// attach this slot to previous conditional
let conditional = dynamicSlots[
dynamicSlots.length - 1
] as ConditionalExpression
while (
conditional.alternate.type === NodeTypes.JS_CONDITIONAL_EXPRESSION
) {
conditional = conditional.alternate
}
conditional.alternate = vElse.exp
? createConditionalExpression(
vElse.exp,
buildDynamicSlot(slotName, slotFunction),
defaultFallback
)
: buildDynamicSlot(slotName, slotFunction)
} else {
context.onError(
createCompilerError(ErrorCodes.X_V_ELSE_NO_ADJACENT_IF, vElse.loc)
)
}
} else if ((vFor = findDir(slotElement, 'for'))) {
hasDynamicSlots = true
const parseResult =
vFor.parseResult ||
parseForExpression(vFor.exp as SimpleExpressionNode, context)
if (parseResult) {
// Render the dynamic slots as an array and add it to the createSlot()
// args. The runtime knows how to handle it appropriately.
dynamicSlots.push(
createCallExpression(context.helper(RENDER_LIST), [
parseResult.source,
createFunctionExpression(
createForLoopParams(parseResult),
buildDynamicSlot(slotName, slotFunction),
true
)
])
)
} else {
context.onError(
createCompilerError(ErrorCodes.X_V_FOR_MALFORMED_EXPRESSION, vFor.loc)
)
}
} else {
// check duplicate static names
if (staticSlotName) {
if (seenSlotNames.has(staticSlotName)) {
context.onError(
createCompilerError(
ErrorCodes.X_V_SLOT_DUPLICATE_SLOT_NAMES,
dirLoc
)
)
continue
}
seenSlotNames.add(staticSlotName)
}
slotsProperties.push(createObjectProperty(slotName, slotFunction))
}
}
if (hasTemplateSlots && extraneousChild) {
context.onError(
createCompilerError(
ErrorCodes.X_V_SLOT_EXTRANEOUS_NON_SLOT_CHILDREN,
extraneousChild.loc
)
)
}
if (!explicitDefaultSlot && !hasTemplateSlots) {
// implicit default slot.
slotsProperties.push(buildDefaultSlot(undefined, children, loc))
}
let slots: ObjectExpression | CallExpression = createObjectExpression(
slotsProperties.concat(
createObjectProperty(`_compiled`, createSimpleExpression(`true`, false))
),
loc
)
if (dynamicSlots.length) {
slots = createCallExpression(context.helper(CREATE_SLOTS), [
slots,
createArrayExpression(dynamicSlots)
])
}
return {
slots,
hasDynamicSlots
}
}
function buildDefaultSlot(
slotProps: ExpressionNode | undefined,
children: TemplateChildNode[],
loc: SourceLocation
): Property {
return createObjectProperty(
`default`,
createFunctionExpression(
slotProps,
children,
false,
children.length ? children[0].loc : loc
)
)
}
function buildDynamicSlot(
name: ExpressionNode,
fn: FunctionExpression
): ObjectExpression {
return createObjectExpression([
createObjectProperty(`name`, name),
createObjectProperty(`fn`, fn)
])
}