Undefined valueDeclaration in props is crashing vls

[javiertury]

• I have searched through existing issues
• I have read through docs
• I have read FAQ

Info

• Platform: Linux
• Vetur version: vls 0.5.4
• VS Code version: Coc-vetur 1.2.0

Problem

Vetur is continuously crashing because s.valueDeclaration can be undefined here:

vetur/server/src/modes/script/componentInfo.ts

Lines 322 to 324 in a733125

	const status = tsModule.isPropertyAssignment(s.valueDeclaration)
	? getPropValidatorInfo(s.valueDeclaration.initializer)
	: { hasObjectValidator: false, required: true };

<project-path>/node_modules/typescript/lib/typescript.js:26110
        return node.kind === 285 /* PropertyAssignment */;
                    ^

TypeError: Cannot read property 'kind' of undefined
    at Object.isPropertyAssignment (<project-path>/node_modules/typescript/lib/typescript.js:26110:21)
    at .../coc-vetur/node_modules/vls/dist/modes/script/componentInfo.js:246:41
    at Array.map (<anonymous>)
    at getObjectProps (.../coc-vetur/node_modules/vls/dist/modes/script/componentInfo.js:245:59)
    at getClassAndObjectInfo (.../coc-vetur/node_modules/vls/dist/modes/script/componentInfo.js:463:35)
    at getProps (.../coc-vetur/node_modules/vls/dist/modes/script/componentInfo.js:65:60)
    at analyzeDefaultExportExpr (.../coc-vetur/node_modules/vls/dist/modes/script/componentInfo.js:39:19)
    at .../coc-vetur/node_modules/vls/dist/modes/script/componentInfo.js:29:45
    at Array.forEach (<anonymous>)
    at Object.getComponentInfo (.../coc-vetur/node_modules/vls/dist/modes/script/componentInfo.js:24:33)

I propose to use instead

                const status = s.valueDeclaration !== undefined && tsModule.isPropertyAssignment(s.valueDeclaration)
                    ? getPropValidatorInfo(s.valueDeclaration.initializer)
                    : { hasObjectValidator: false, required: true };

Reproducible Case

Debugging the issue the problem is the line value: T | undefined (obtained from s.declarations[0].getText()). This line is part of the following fragment.

type Base = Record<string, unknown>;

export type Props <T extends Base = Base> = {
  value: T | undefined
};

Later this type is used to build properties:

// Helper
export type PropsOptions <Props> = {
  [K in keyof Props]: PropOptions<Props[K]>
};

// Properties options
const props: PropOptions<Props<Resource>> = {
  value: {
     type: Object as () => Resource | undefined,
     default: undefined
  }
};

// Component
export default defineComponent({
  props,
  setup(props, { root: { $router } }) {
     ...
  }
});

And also used in parents to create an object of properties that will be binded to the component.

// In parent component, script
const resourceProps: Props<Resource> = {
  value: resource
};

// In parent component, template
v-bind="resourceProps"

EDIT: fix code typo

[yoyo930021]

I don't think it's legal to write in vue.js.

The right way:

import { PropType } from 'vue'

// Properties options
const props = {
  value: {
     type: Function as PropType<() => Reource | undefined>,
     required: false
  }
};

// Component
export default defineComponent({
  props,
  setup(props, { root: { $router } }) {
     ...
  }
});

But I agree we need to deal with this crash.

[javiertury]

Before vetur gained support to check properties in templates, the scheme above was the only way to reliably check property types in both parent and child components.

But now I agree, the scheme I used above should not be used.