Fix/2430 sync modifier prop type checking #2431
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Update from source
v-bind modifiers should always be culled from the node name, because we cannot bind one Vue prop twice (duplicates for v-bind are an error), and so that we aren't trying to find a prop with name "item.sync" rather than "item".
| @@ -251,7 +251,7 @@ export function getTemplateTransformFunctions(ts: T_TypeScript, childComponentNa | |||
| // Attribute name is specified | |||
| // e.g. v-bind:value="foo" | |||
| const fullName = | |||
| dir.key.modifiers.length === 0 | |||
| dir.key.modifiers.length === 0 || !isVOn(dir) | |||
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I think && isVBind(dir) more intuitive.
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@yoyo930021 I agree, and initially that's what I did. However, for reasons that are not clear to me, using isVBind with the typeguard type predicate of : node is AST.VDirective results in line 256 throwing this TypeScript error: Property 'key' does not exist on type 'never'. for the section ...dir.key.modifiers.map.
This doesn't make sense to me, because dir is already of type AST.VDirective in the function parameters. I couldn't figure out a solution, if you know one please let me know.
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After reading a little more, typeguards that are type predicates only do one thing: confirm the type is guarded.
isVBind actually should be split into two methods, one for isVDirective and one for isVBind. isVDirective should be a type guard, e.g. function isVDirective(node: AST.VAttribute | AST.VDirective): node is AST.VDirective {
and isVBind should not be a type guard: function isVBind(node: AST.VAttribute | AST.VDirective): boolean {
Type guard functions that use type predicates only do one thing: They confirm that the type of the parameter is as specified in the predicate. However, functions like `isVBind` were also checking string properties to check the content of the object structure, which made them do more than just confirm that the type is VDirective. This meant that the functions were being used as conditionals for more than just their type guarding, giving unexpected results. The solution is to create a function, `isVDirective`, which is the type guard for `node is AST.VDirective`, and change the returns of the other `isVX` functions to be `boolean`.
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@ktsn If you have time, you can take a look. |
Fixes #2430