vue3-yuanma/packages/compiler-core/src/transforms/vOn.ts
2019-09-24 22:39:20 -04:00

42 lines
1.4 KiB
TypeScript

import { DirectiveTransform } from '../transform'
import { createObjectProperty, createExpression, ExpressionNode } from '../ast'
import { capitalize } from '@vue/shared'
import { createCompilerError, ErrorCodes } from '../errors'
import { isSimpleIdentifier } from '../utils'
// v-on without arg is handled directly in ./element.ts due to it affecting
// codegen for the entire props object. This transform here is only for v-on
// *with* args.
export const transformOn: DirectiveTransform = ({ arg, exp, loc }, context) => {
if (!exp) {
context.onError(createCompilerError(ErrorCodes.X_V_ON_NO_EXPRESSION, loc))
}
const { content, children, isStatic, loc: argLoc } = arg!
let eventName: ExpressionNode
if (isStatic) {
// static arg
eventName = createExpression(`on${capitalize(content)}`, true, argLoc)
} else if (!children) {
// dynamic arg with no rewrite
eventName = createExpression(
`"on" + ${isSimpleIdentifier(content) ? content : `(${content})`}`,
false,
argLoc
)
} else {
// dynamic arg with ctx prefixing
eventName = arg!
children.unshift(`"on" + `)
}
// TODO .once modifier handling since it is platform agnostic
// other modifiers are handled in compiler-dom
return {
props: createObjectProperty(
eventName,
exp || createExpression(`() => {}`, false, loc),
loc
),
needRuntime: false
}
}