feat(linter/plugins): implement SourceCode#getTokenAfter()

apps/oxlint/src-js/plugins/tokens.ts

@@ -527,14 +527,90 @@ export function getTokensBefore(
  * @param skipOptions? - Options object. Same options as `getFirstToken()`.
  * @returns `Token`, or `null` if all were skipped.
  */
-/* oxlint-disable no-unused-vars */
 export function getTokenAfter(
   nodeOrToken: NodeOrToken | Comment,
   skipOptions?: SkipOptions | number | FilterFn | null,
 ): Token | null {
-  throw new Error('`sourceCode.getTokenAfter` not implemented yet'); // TODO
+  if (tokens === null) initTokens();
+  debugAssertIsNonNull(tokens);
+  debugAssertIsNonNull(comments);
+
+  let skip =
+    typeof skipOptions === 'number'
+      ? skipOptions
+      : typeof skipOptions === 'object' && skipOptions !== null
+        ? (skipOptions.skip ?? 0)
+        : 0;
+
+  const filter =
+    typeof skipOptions === 'function'
+      ? skipOptions
+      : typeof skipOptions === 'object' && skipOptions !== null
+        ? skipOptions.filter
+        : null;
+
+  const includeComments =
+    typeof skipOptions === 'object' &&
+    skipOptions !== null &&
+    'includeComments' in skipOptions &&
+    skipOptions.includeComments;
+
+  // Source array of tokens to search in
+  let nodeTokens: Token[] | null = null;
+  if (includeComments) {
+    if (tokensWithComments === null) {
+      tokensWithComments = [...tokens, ...comments].sort((a, b) => a.range[0] - b.range[0]);
+    }
+    nodeTokens = tokensWithComments;
+  } else {
+    nodeTokens = tokens;
+  }
+
+  const { range } = nodeOrToken,
+    rangeEnd = range[1];
+
+  // Binary search for the first token that starts at or after the end of the node/token
+  const tokensLength = nodeTokens.length;
+  let startIndex = tokensLength;
+  for (let lo = 0; lo < startIndex; ) {
+    const mid = (lo + startIndex) >> 1;
+    if (nodeTokens[mid].range[0] < rangeEnd) {
+      lo = mid + 1;
+    } else {
+      startIndex = mid;
+    }
+  }
+
+  // Fast path for the common case
+  if (typeof filter !== 'function') {
+    if (typeof skip !== 'number') {
+      return nodeTokens[startIndex] ?? null;
+    } else {
+      return nodeTokens[startIndex + skip] ?? null;
+    }
+  } else {
+    if (typeof skip !== 'number') {
+      for (let i = startIndex; i < tokensLength; i++) {
+        const token = nodeTokens[i];
+        if (filter(token)) {
+          return token;
+        }
+      }
+    } else {
+      for (let i = startIndex; i < tokensLength; i++) {
+        const token = nodeTokens[i];
+        if (filter(token)) {
+          if (skip === 0) {
+            return token;
+          }
+          skip--;
+        }
+      }
+    }
+  }
+
+  return null;
 }
-/* oxlint-enable no-unused-vars */
 
 /**
  * Get the token that follows a given node or token.

apps/oxlint/test/tokens.test.ts

@@ -303,11 +303,105 @@ describe('when calling getTokenBefore', () => {
   });
 });
 
+// https://github.com/eslint/eslint/blob/v9.39.1/tests/lib/languages/js/source-code/token-store.js#L461
 describe('when calling getTokenAfter', () => {
-  /* oxlint-disable-next-line no-disabled-tests expect-expect */
-  it('is to be implemented');
-  /* oxlint-disable-next-line no-unused-expressions */
-  getTokenAfter;
+  it('should retrieve one token after a node', () => {
+    assert.strictEqual(getTokenAfter(VariableDeclaratorIdentifier)!.value, '=');
+  });
+
+  it('should skip a given number of tokens', () => {
+    assert.strictEqual(getTokenAfter(VariableDeclaratorIdentifier, 1)!.value, 'a');
+    assert.strictEqual(getTokenAfter(VariableDeclaratorIdentifier, 2)!.value, '*');
+  });
+
+  it('should skip a given number of tokens with skip option', () => {
+    assert.strictEqual(getTokenAfter(VariableDeclaratorIdentifier, { skip: 1 })!.value, 'a');
+    assert.strictEqual(getTokenAfter(VariableDeclaratorIdentifier, { skip: 2 })!.value, '*');
+  });
+
+  it('should retrieve matched token with filter option', () => {
+    assert.strictEqual(getTokenAfter(VariableDeclaratorIdentifier, (t) => t.type === 'Identifier')!.value, 'a');
+    assert.strictEqual(
+      getTokenAfter(VariableDeclaratorIdentifier, {
+        filter: (t) => t.type === 'Identifier',
+      })!.value,
+      'a',
+    );
+  });
+
+  it('should retrieve matched token with filter and skip options', () => {
+    assert.strictEqual(
+      getTokenAfter(VariableDeclaratorIdentifier, {
+        skip: 1,
+        filter: (t) => t.type === 'Identifier',
+      })!.value,
+      'b',
+    );
+  });
+
+  it('should retrieve one token or comment after a node with includeComments option', () => {
+    assert.strictEqual(
+      getTokenAfter(VariableDeclaratorIdentifier, {
+        includeComments: true,
+      })!.value,
+      'B',
+    );
+  });
+
+  it('should retrieve one token or comment after a node with includeComments and skip options', () => {
+    assert.strictEqual(
+      getTokenAfter(VariableDeclaratorIdentifier, {
+        includeComments: true,
+        skip: 2,
+      })!.value,
+      'C',
+    );
+  });
+
+  it('should retrieve one token or comment after a node with includeComments and skip and filter options', () => {
+    assert.strictEqual(
+      getTokenAfter(VariableDeclaratorIdentifier, {
+        includeComments: true,
+        skip: 2,
+        filter: (t) => t.type.startsWith('Block'),
+      })!.value,
+      'D',
+    );
+  });
+
+  it('should retrieve the next node if the comment at the first of source code is specified.', () => {
+    resetSourceAndAst();
+    sourceText = '/*comment*/ a + b';
+    // TODO: replace this verbatim range with `ast.comments[0]`
+    const token = getTokenAfter({ range: [0, 12] } as Node)!;
+
+    assert.strictEqual(token.value, 'a');
+    resetSourceAndAst();
+  });
+
+  it('should retrieve the next comment if the last token is specified.', () => {
+    resetSourceAndAst();
+    sourceText = 'a + b /*comment*/';
+    // TODO: replace this verbatim range with `ast.tokens[2]`
+    const token = getTokenAfter({ range: [4, 5] } as Node, {
+      includeComments: true,
+    });
+
+    assert.strictEqual(token!.value, 'comment');
+    resetSourceAndAst();
+  });
+
+  it('should retrieve null if the last comment is specified.', () => {
+    resetSourceAndAst();
+    sourceText = 'a + b /*comment*/';
+    // TODO: replace this verbatim range with `ast.comments[0]`
+    const token = getTokenAfter({ range: [6, 17] } as Node, {
+      includeComments: true,
+    });
+
+    assert.strictEqual(token, null);
+    resetSourceAndAst();
+  });
 });
 
 // https://github.com/eslint/eslint/blob/v9.39.1/tests/lib/languages/js/source-code/token-store.js#L363-L459