sgrep

sgrep performs structural search over TS/JS source files using metavariable templates.

Pattern input can be:

• inline pattern text
• a file path (resolved from cwd)

Install

npm install --save-dev @claudiu-ceia/sgrep

CLI

sgrep \
  [--json] \
  [--no-color] \
  [--no-isomorphisms] \
  [--cwd <path>] \
  [--concurrency <n>] \
  [--verbose <level>] \
  <pattern-input> [scope]

# through umbrella CLI
astkit search \
  [--json] \
  [--no-color] \
  [--no-isomorphisms] \
  [--cwd <path>] \
  [--concurrency <n>] \
  [--verbose <level>] \
  <pattern-input> [scope]

Flags:

• --json: output structured JSON
• --no-color: disable colored output in compact text mode
• --no-isomorphisms: disable isomorphism expansion
• --cwd <path>: working directory for resolving pattern file and scope
• --concurrency <n>: max files processed concurrently (default: 8)
• --verbose <level>: perf tracing to stderr (1=summary, 2=includes slow files)

Quick examples

# inline pattern
sgrep 'const :[name] = :[value];' src

# pattern from file
sgrep rules/find-const.sgrep src --cwd /repo

# inspect expanded-match behavior and perf tracing
sgrep 'const obj = { a: :[x], b: :[y] };' src --verbose 2

Pattern syntax

Supported syntax is shared with spatch templates:

• :[name]
• :[_] anonymous hole (not captured)
• :[name~regex] regex-constrained hole
• ... variadic wildcard

Repeated named holes enforce equality:

:[x] + :[x]

Matches foo + foo, not foo + bar.

Regex-constrained holes intentionally use a safe subset:

• max regex constraint length: 256
• unsupported constructs: lookarounds, backreferences, inline modifier groups, legacy octal escapes, and incomplete control escapes
• rejected ambiguous structures: more than 256 cumulative ambiguity expansions across alternatives, sequences, and bounded repetitions; overlapping variable sibling repetitions; unbounded repetition of nullable or ambiguous alternatives; and compounding nested quantifiers
• bounded quantifiers are limited to 2048 cumulative work units; deterministic non-nullable ranges do not consume ambiguity expansions
• constrained captures longer than 2048 characters are rejected

Example with variadic wildcard:

foo(:[x], ..., :[y])

Matches calls where :[x] is the first argument and :[y] is the last argument.

Structural balancing

Hole captures are required to be structurally balanced:

• parentheses, brackets, and braces
• quoted strings (single, double, template)
• line and block comments

This prevents partial malformed captures.

Isomorphisms

sgrep expands patterns through a small isomorphism engine before matching.

The default rule only adds redundant parentheses around binary expressions. It does not remove parentheses or reorder expressions, because those transformations are not generally sound in JavaScript.

The programmatic UNSAFE_ISOMORPHISM_RULES export retains operand and object-property reordering for specialized callers that can guarantee purity and compatible operand types.

Disable all isomorphisms with:

sgrep 'const total = :[x] + :[y];' src --no-isomorphisms

Patterns containing template wildcard ... intentionally skip AST-based isomorphism expansion to avoid ambiguity with JS spread syntax.

Output modes

• Default output is compact text grouped by file.
• --json returns the full result object for machine consumers.

Safety model

• Scope and pattern-input file paths are constrained to the nearest git repository root when available.
• If no git root is found, paths are constrained to cwd.
• Compact output escapes control characters in matched previews and file paths.

Programmatic API

import {
  DEFAULT_ISOMORPHISM_RULES,
  DEFAULT_SEARCH_EXCLUDED_DIRECTORIES,
  DEFAULT_SEARCHABLE_EXTENSIONS,
  expandPatternIsomorphisms,
  formatSearchOutput,
  runSearchCommand,
  searchProject,
  type ExpandIsomorphismsOptions,
  type IsomorphismRule,
  type SearchCommandFlags,
  type SgrepOptions,
  type SgrepResult,
} from "@claudiu-ceia/sgrep";

Core APIs:

• searchProject(patternInput, options?)
• runSearchCommand(patternInput, scope, flags) for CLI embedding
• formatSearchOutput(result, { color? }) for compact text formatting
• expandPatternIsomorphisms(pattern, options?) for rule-driven expansion

Result schema

searchProject and runSearchCommand return:

type SgrepResult = {
  scope: string;
  pattern: string;
  filesScanned: number;
  filesMatched: number;
  totalMatches: number;
  elapsedMs: number;
  files: Array<{
    file: string;
    matchCount: number;
    matches: Array<{
      start: number;
      end: number;
      line: number;
      character: number;
      matched: string;
      captures: Record<string, string>;
    }>;
  }>;
};

Development

From monorepo root:

bun run sgrep -- --help
bun test packages/sgrep/__tests__
bun test --coverage packages/sgrep/__tests__
bun run typecheck