Use type predicate for getFirstJSDocTag (microsoft#22573)

Andy · web-flow · commit 5f1668e53df1 · 2018-03-14T12:40:30.000-07:00
* Use type predicate for getFirstJSDocTag

* Restore API
diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
@@ -21471,7 +21471,7 @@ namespace ts {
                 return;
             }
 
-            const augmentsTags = getAllJSDocTagsOfKind(classLike, SyntaxKind.JSDocAugmentsTag);
+            const augmentsTags = getJSDocTags(classLike).filter(isJSDocAugmentsTag);
             Debug.assert(augmentsTags.length > 0);
             if (augmentsTags.length > 1) {
                 error(augmentsTags[1], Diagnostics.Class_declarations_cannot_have_more_than_one_augments_or_extends_tag);
diff --git a/src/compiler/utilities.ts b/src/compiler/utilities.ts
@@ -4435,33 +4435,33 @@ namespace ts {
      * for example on a variable declaration whose initializer is a function expression.
      */
     export function hasJSDocParameterTags(node: FunctionLikeDeclaration | SignatureDeclaration): boolean {
-        return !!getFirstJSDocTag(node, SyntaxKind.JSDocParameterTag);
+        return !!getFirstJSDocTag(node, isJSDocParameterTag);
     }
 
     /** Gets the JSDoc augments tag for the node if present */
     export function getJSDocAugmentsTag(node: Node): JSDocAugmentsTag | undefined {
-        return getFirstJSDocTag(node, SyntaxKind.JSDocAugmentsTag) as JSDocAugmentsTag;
+        return getFirstJSDocTag(node, isJSDocAugmentsTag);
     }
 
     /** Gets the JSDoc class tag for the node if present */
     export function getJSDocClassTag(node: Node): JSDocClassTag | undefined {
-        return getFirstJSDocTag(node, SyntaxKind.JSDocClassTag) as JSDocClassTag;
+        return getFirstJSDocTag(node, isJSDocClassTag);
     }
 
     /** Gets the JSDoc return tag for the node if present */
     export function getJSDocReturnTag(node: Node): JSDocReturnTag | undefined {
-        return getFirstJSDocTag(node, SyntaxKind.JSDocReturnTag) as JSDocReturnTag;
+        return getFirstJSDocTag(node, isJSDocReturnTag);
     }
 
     /** Gets the JSDoc template tag for the node if present */
     export function getJSDocTemplateTag(node: Node): JSDocTemplateTag | undefined {
-        return getFirstJSDocTag(node, SyntaxKind.JSDocTemplateTag) as JSDocTemplateTag;
+        return getFirstJSDocTag(node, isJSDocTemplateTag);
     }
 
     /** Gets the JSDoc type tag for the node if present and valid */
     export function getJSDocTypeTag(node: Node): JSDocTypeTag | undefined {
         // We should have already issued an error if there were multiple type jsdocs, so just use the first one.
-        const tag = getFirstJSDocTag(node, SyntaxKind.JSDocTypeTag) as JSDocTypeTag;
+        const tag = getFirstJSDocTag(node, isJSDocTypeTag);
         if (tag && tag.typeExpression && tag.typeExpression.type) {
             return tag;
         }
@@ -4480,7 +4480,7 @@ namespace ts {
      * tag directly on the node would be returned.
      */
     export function getJSDocType(node: Node): TypeNode | undefined {
-        let tag: JSDocTypeTag | JSDocParameterTag = getFirstJSDocTag(node, SyntaxKind.JSDocTypeTag) as JSDocTypeTag;
+        let tag: JSDocTypeTag | JSDocParameterTag | undefined = getFirstJSDocTag(node, isJSDocTypeTag);
         if (!tag && isParameter(node)) {
             tag = find(getJSDocParameterTags(node), tag => !!tag.typeExpression);
         }
@@ -4500,7 +4500,7 @@ namespace ts {
     }
 
     /** Get all JSDoc tags related to a node, including those on parent nodes. */
-    export function getJSDocTags(node: Node): ReadonlyArray<JSDocTag> | undefined {
+    export function getJSDocTags(node: Node): ReadonlyArray<JSDocTag> {
         let tags = (node as JSDocContainer).jsDocCache;
         // If cache is 'null', that means we did the work of searching for JSDoc tags and came up with nothing.
         if (tags === undefined) {
@@ -4510,17 +4510,14 @@ namespace ts {
     }
 
     /** Get the first JSDoc tag of a specified kind, or undefined if not present. */
-    function getFirstJSDocTag(node: Node, kind: SyntaxKind): JSDocTag | undefined {
-        const tags = getJSDocTags(node);
-        return find(tags, doc => doc.kind === kind);
+    function getFirstJSDocTag<T extends JSDocTag>(node: Node, predicate: (tag: JSDocTag) => tag is T): T | undefined {
+        return find(getJSDocTags(node), predicate);
     }
 
     /** Gets all JSDoc tags of a specified kind, or undefined if not present. */
     export function getAllJSDocTagsOfKind(node: Node, kind: SyntaxKind): ReadonlyArray<JSDocTag> | undefined {
-        const tags = getJSDocTags(node);
-        return filter(tags, doc => doc.kind === kind);
+        return getJSDocTags(node).filter(doc => doc.kind === kind);
     }
-
 }
 
 // Simple node tests of the form `node.kind === SyntaxKind.Foo`.
@@ -5163,6 +5160,10 @@ namespace ts {
         return node.kind === SyntaxKind.JSDocAugmentsTag;
     }
 
+    export function isJSDocClassTag(node: Node): node is JSDocClassTag {
+        return node.kind === SyntaxKind.JSDocClassTag;
+    }
+
     export function isJSDocParameterTag(node: Node): node is JSDocParameterTag {
         return node.kind === SyntaxKind.JSDocParameterTag;
     }
diff --git a/tests/baselines/reference/api/tsserverlibrary.d.ts b/tests/baselines/reference/api/tsserverlibrary.d.ts
@@ -3034,7 +3034,7 @@ declare namespace ts {
      */
     function getJSDocReturnType(node: Node): TypeNode | undefined;
     /** Get all JSDoc tags related to a node, including those on parent nodes. */
-    function getJSDocTags(node: Node): ReadonlyArray<JSDocTag> | undefined;
+    function getJSDocTags(node: Node): ReadonlyArray<JSDocTag>;
     /** Gets all JSDoc tags of a specified kind, or undefined if not present. */
     function getAllJSDocTagsOfKind(node: Node, kind: SyntaxKind): ReadonlyArray<JSDocTag> | undefined;
 }
@@ -3190,6 +3190,7 @@ declare namespace ts {
     function isJSDocVariadicType(node: Node): node is JSDocVariadicType;
     function isJSDoc(node: Node): node is JSDoc;
     function isJSDocAugmentsTag(node: Node): node is JSDocAugmentsTag;
+    function isJSDocClassTag(node: Node): node is JSDocClassTag;
     function isJSDocParameterTag(node: Node): node is JSDocParameterTag;
     function isJSDocReturnTag(node: Node): node is JSDocReturnTag;
     function isJSDocTypeTag(node: Node): node is JSDocTypeTag;
diff --git a/tests/baselines/reference/api/typescript.d.ts b/tests/baselines/reference/api/typescript.d.ts
@@ -3089,7 +3089,7 @@ declare namespace ts {
      */
     function getJSDocReturnType(node: Node): TypeNode | undefined;
     /** Get all JSDoc tags related to a node, including those on parent nodes. */
-    function getJSDocTags(node: Node): ReadonlyArray<JSDocTag> | undefined;
+    function getJSDocTags(node: Node): ReadonlyArray<JSDocTag>;
     /** Gets all JSDoc tags of a specified kind, or undefined if not present. */
     function getAllJSDocTagsOfKind(node: Node, kind: SyntaxKind): ReadonlyArray<JSDocTag> | undefined;
 }
@@ -3245,6 +3245,7 @@ declare namespace ts {
     function isJSDocVariadicType(node: Node): node is JSDocVariadicType;
     function isJSDoc(node: Node): node is JSDoc;
     function isJSDocAugmentsTag(node: Node): node is JSDocAugmentsTag;
+    function isJSDocClassTag(node: Node): node is JSDocClassTag;
     function isJSDocParameterTag(node: Node): node is JSDocParameterTag;
     function isJSDocReturnTag(node: Node): node is JSDocReturnTag;
     function isJSDocTypeTag(node: Node): node is JSDocTypeTag;

Original file line number	Diff line number	Diff line change
`@@ -21471,7 +21471,7 @@ namespace ts {`
`21471`	`21471`	`return;`
`21472`	`21472`	`}`
`21473`	`21473`
`21474`		`- const augmentsTags = getAllJSDocTagsOfKind(classLike, SyntaxKind.JSDocAugmentsTag);`
	`21474`	`+ const augmentsTags = getJSDocTags(classLike).filter(isJSDocAugmentsTag);`
`21475`	`21475`	`Debug.assert(augmentsTags.length > 0);`
`21476`	`21476`	`if (augmentsTags.length > 1) {`
`21477`	`21477`	`error(augmentsTags[1], Diagnostics.Class_declarations_cannot_have_more_than_one_augments_or_extends_tag);`