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

Author: lilnasy

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

@@ -1094,20 +1094,106 @@ export function getLastTokenBetween(
 
 /**
  * Get the last tokens between two non-overlapping nodes.
- * @param nodeOrToken1 - Node before the desired token range.
- * @param nodeOrToken2 - Node after the desired token range.
+ * @param left - Node before the desired token range.
+ * @param right - Node after the desired token range.
  * @param countOptions? - Options object. Same options as `getFirstTokens()`.
- * @returns Array of `Token`s between `nodeOrToken1` and `nodeOrToken2`.
+ * @returns Array of `Token`s between `left` and `right`.
  */
-/* oxlint-disable no-unused-vars */
 export function getLastTokensBetween(
-  nodeOrToken1: NodeOrToken | Comment,
-  nodeOrToken2: NodeOrToken | Comment,
+  left: NodeOrToken | Comment,
+  right: NodeOrToken | Comment,
   countOptions?: CountOptions | number | FilterFn | null,
 ): Token[] {
-  throw new Error('`sourceCode.getLastTokensBetween` not implemented yet'); // TODO
+  if (tokens === null) initTokens();
+  debugAssertIsNonNull(tokens);
+  debugAssertIsNonNull(comments);
+
+  const count =
+    typeof countOptions === 'number'
+      ? countOptions
+      : typeof countOptions === 'object' && countOptions !== null
+        ? countOptions.count
+        : null;
+
+  const filter =
+    typeof countOptions === 'function'
+      ? countOptions
+      : typeof countOptions === 'object' && countOptions !== null
+        ? countOptions.filter
+        : null;
+
+  const includeComments =
+    typeof countOptions === 'object' &&
+    countOptions !== null &&
+    'includeComments' in countOptions &&
+    countOptions.includeComments;
+
+  let nodeTokens: Token[] | null = null;
+  if (includeComments) {
+    if (tokensWithComments === null) initTokensWithComments();
+    debugAssertIsNonNull(tokensWithComments);
+    nodeTokens = tokensWithComments;
+  } else {
+    nodeTokens = tokens;
+  }
+
+  const rangeStart = left.range[1],
+    rangeEnd = right.range[0],
+    tokensLength = nodeTokens.length;
+
+  // Binary search for first token past the beginning of the `between` range
+  let sliceStart = tokensLength;
+  for (let lo = 0; lo < sliceStart; ) {
+    const mid = (lo + sliceStart) >> 1;
+    if (nodeTokens[mid].range[0] < rangeStart) {
+      lo = mid + 1;
+    } else {
+      sliceStart = mid;
+    }
+  }
+
+  // Binary search for first token past the end of the `between` range
+  let sliceEnd = tokensLength;
+  for (let lo = sliceStart; lo < sliceEnd; ) {
+    const mid = (lo + sliceEnd) >> 1;
+    if (nodeTokens[mid].range[0] < rangeEnd) {
+      lo = mid + 1;
+    } else {
+      sliceEnd = mid;
+    }
+  }
+
+  let tokensBetween: Token[];
+  // Fast path for the common case
+  if (typeof filter !== 'function') {
+    if (typeof count !== 'number') {
+      tokensBetween = nodeTokens.slice(sliceStart, sliceEnd);
+    } else {
+      tokensBetween = nodeTokens.slice(max(sliceStart, sliceEnd - count), sliceEnd);
+    }
+  } else {
+    if (typeof count !== 'number') {
+      tokensBetween = [];
+      for (let i = sliceStart; i < sliceEnd; i++) {
+        const token = nodeTokens[i];
+        if (filter(token)) {
+          tokensBetween.push(token);
+        }
+      }
+    } else {
+      tokensBetween = [];
+      // Count is the number of preceding tokens so we iterate in reverse
+      for (let i = sliceEnd - 1; i >= sliceStart && tokensBetween.length < count; i--) {
+        const token = nodeTokens[i];
+        if (filter(token)) {
+          tokensBetween.unshift(token);
+        }
+      }
+    }
+  }
+
+  return tokensBetween;
 }
-/* oxlint-enable no-unused-vars */
 
 /**
  * Get the token starting at the specified index.

apps/oxlint/test/tokens.test.ts

@@ -20,6 +20,7 @@ import {
 } from '../src-js/plugins/tokens.js';
 import { resetSourceAndAst } from '../src-js/plugins/source_code.js';
 import type { Node } from '../src-js/plugins/types.js';
+import type { BinaryExpression } from '../src-js/generated/types.js';
 
 // Source text used for most tests
 const SOURCE_TEXT = '/*A*/var answer/*B*/=/*C*/a/*D*/* b/*E*///F\n    call();\n/*Z*/';
@@ -50,8 +51,13 @@ beforeEach(() => {
 // https://eslint.org/blog/2025/10/whats-coming-in-eslint-10.0.0/#updates-to-program-ast-node-range-coverage
 // https://github.com/typescript-eslint/typescript-eslint/issues/11026#issuecomment-3421887632
 const Program = { range: [5, 55] } as Node;
-const BinaryExpression = { range: [26, 35] } as Node;
+const BinaryExpression = {
+  range: [26, 35],
+  left: { range: [26, 27] } as Node,
+  right: { range: [34, 35] } as Node,
+} as BinaryExpression;
 const VariableDeclaratorIdentifier = { range: [9, 15] } as Node;
+const CallExpression = { range: [48, 54] } as Node;
 
 // https://github.com/eslint/eslint/blob/v9.39.1/tests/lib/languages/js/source-code/token-store.js#L62
 describe('when calling getTokens', () => {
@@ -734,11 +740,62 @@ describe('when calling getFirstTokenBetween', () => {
   getFirstTokenBetween;
 });
 
+// https://github.com/eslint/eslint/blob/v9.39.1/tests/lib/languages/js/source-code/token-store.js#L1298-L1382
 describe('when calling getLastTokensBetween', () => {
-  /* oxlint-disable-next-line no-disabled-tests expect-expect */
-  it('is to be implemented');
-  /* oxlint-disable-next-line no-unused-expressions */
-  getLastTokensBetween;
+  it('should retrieve zero tokens between adjacent nodes', () => {
+    expect(getLastTokensBetween(BinaryExpression, CallExpression).map((token) => token.value)).toEqual([]);
+  });
+
+  it('should retrieve multiple tokens between non-adjacent nodes with count option', () => {
+    expect(
+      getLastTokensBetween(VariableDeclaratorIdentifier, BinaryExpression.right, 2).map((token) => token.value),
+    ).toEqual(['a', '*']);
+    expect(
+      getLastTokensBetween(VariableDeclaratorIdentifier, BinaryExpression.right, { count: 2 }).map(
+        (token) => token.value,
+      ),
+    ).toEqual(['a', '*']);
+  });
+
+  it('should retrieve matched tokens between non-adjacent nodes with filter option', () => {
+    expect(
+      getLastTokensBetween(VariableDeclaratorIdentifier, BinaryExpression.right, {
+        filter: (t) => t.type !== 'Punctuator',
+      }).map((token) => token.value),
+    ).toEqual(['a']);
+  });
+
+  it('should retrieve all tokens between non-adjacent nodes with empty object option', () => {
+    expect(
+      getLastTokensBetween(VariableDeclaratorIdentifier, BinaryExpression.right, {}).map((token) => token.value),
+    ).toEqual(['=', 'a', '*']);
+  });
+
+  it('should retrieve all tokens and comments between non-adjacent nodes with includeComments option', () => {
+    expect(
+      getLastTokensBetween(VariableDeclaratorIdentifier, BinaryExpression.right, { includeComments: true }).map(
+        (token) => token.value,
+      ),
+    ).toEqual(['B', '=', 'C', 'a', 'D', '*']);
+  });
+
+  it('should retrieve multiple tokens between non-adjacent nodes with includeComments and count options', () => {
+    expect(
+      getLastTokensBetween(VariableDeclaratorIdentifier, BinaryExpression.right, {
+        includeComments: true,
+        count: 3,
+      }).map((token) => token.value),
+    ).toEqual(['a', 'D', '*']);
+  });
+
+  it('should retrieve multiple tokens and comments between non-adjacent nodes with includeComments and filter options', () => {
+    expect(
+      getLastTokensBetween(VariableDeclaratorIdentifier, BinaryExpression.right, {
+        includeComments: true,
+        filter: (t) => t.type !== 'Punctuator',
+      }).map((token) => token.value),
+    ).toEqual(['B', 'C', 'a', 'D']);
+  });
 });
 
 describe('when calling getLastTokenBetween', () => {