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chore(event): resolve strictNullCheck errors in event-decorator #3590

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Merged
rwaskiewicz merged 3 commits into from
Sep 12, 2022
Merged

chore(event): resolve strictNullCheck errors in event-decorator #3590

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94098e6
chore(event): resolve strictNullCheck errors in event-decorator
rwaskiewicz Sep 8, 2022
5c296cf
review(ap): update jsdoc to take `null` into account
rwaskiewicz Sep 12, 2022
8efb828
Merge branch 'main' into rwaskiewicz/event-emitter-snc
rwaskiewicz Sep 12, 2022
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39 changes: 36 additions & 3 deletions src/compiler/transformers/decorators-to-static/event-decorator.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -27,12 +27,22 @@ export const eventDecoratorsToStatic = (
}
};

/**
* Parse a single instance of Stencil's `@Event()` decorator and generate metadata for the class member that is
* decorated
* @param diagnostics a list of diagnostics used as a part of the parsing process. Any parse errors/warnings shall be
* added to this collection
* @param typeChecker an instance of the TypeScript type checker, used to generate information about the `@Event()` and
* its surrounding context in the AST
* @param prop the property on the Stencil component class that is decorated with `@Event()`
* @returns generated metadata for the class member decorated by `@Event()`, or `null` if none could be derived
*/
const parseEventDecorator = (
diagnostics: d.Diagnostic[],
typeChecker: ts.TypeChecker,
prop: ts.PropertyDeclaration
): d.ComponentCompilerStaticEvent => {
const eventDecorator = prop.decorators.find(isDecoratorNamed('Event'));
): d.ComponentCompilerStaticEvent | null => {
const eventDecorator = prop.decorators?.find(isDecoratorNamed('Event'));

if (eventDecorator == null) {
return null;
Expand Down Expand Up @@ -70,6 +80,12 @@ export const getEventName = (eventOptions: d.EventOptions, memberName: string) =
return memberName;
};

/**
* Derive Stencil's class member type metadata from a node in the AST
* @param typeChecker the TypeScript type checker
* @param node the node in the AST to generate metadata for
* @returns the generated metadata
*/
const getComplexType = (
typeChecker: ts.TypeChecker,
node: ts.PropertyDeclaration
Expand All @@ -83,6 +99,11 @@ const getComplexType = (
};
};

/**
* Derive the type of the event from the typings of `EventEmitter`
* @param type the AST node containing the `EventEmitter` typing
* @returns the type taken from `EventEmitter`, or `null` if the type cannot be derived
*/
const getEventType = (type: ts.TypeNode): ts.TypeNode | null => {
if (
ts.isTypeReferenceNode(type) &&
Expand All @@ -96,7 +117,18 @@ const getEventType = (type: ts.TypeNode): ts.TypeNode | null => {
return null;
};

const validateEventName = (diagnostics: d.Diagnostic[], node: ts.Node, eventName: string) => {
/**
* Helper function for validating the name of the event
*
* This function assumes that the name of the event has been determined prior to calling it
*
* @param diagnostics a list of diagnostics used as a part of the validation process. Any parse errors/warnings shall be
* added to this collection
* @param node the node in the AT containing the class member decorated with `@Event()`
* @param eventName the name of the event
*/
const validateEventName = (diagnostics: d.Diagnostic[], node: ts.Node, eventName: string): void => {
// this regex checks for a string that begins with a capital letter - e.g. 'AskJeeves', 'Zoo', 'Spotify'
if (/^[A-Z]/.test(eventName)) {
const diagnostic = buildWarn(diagnostics);
diagnostic.messageText = [
Expand All @@ -108,6 +140,7 @@ const validateEventName = (diagnostics: d.Diagnostic[], node: ts.Node, eventName
return;
}

// this regex checks for a string that begins 'on', followed by a capital letter - e.g. 'onAbout', 'onZing', 'onBlur'
if (/^on[A-Z]/.test(eventName)) {
const warn = buildWarn(diagnostics);
const suggestedEventName = eventName[2].toLowerCase() + eventName.slice(3);
Expand Down