regexp-tree-cli

0.0.21 verified Fri May 01 auth: no javascript

Command-line interface for the regexp-tree library (v0.0.21). Parses, optimizes, and transpiles JavaScript/ECMAScript regular expressions, producing ASTs with loc support, NFA/DFA transition tables, and compatibility transpilation. Unlike regex libraries that only match or replace, regexp-tree-cli operates at the AST level for transformations and analysis. Primarily a CLI tool, but can be used programmatically via the regexp-tree package. Last stable release is v0.0.21; development is infrequent but the underlying regexp-tree library is more actively maintained.

Common errors

error ReferenceError: regexp-tree-cli is not defined ↓

cause Trying to import the CLI package directly in Node.js code instead of using the command line.

fix

Use the CLI from the terminal, or import 'regexp-tree' for programmatic use.

error Error: Invalid regular expression: / /: Nothing to repeat ↓

cause Passing an expression without slashes or with an empty regex.

fix

Wrap in slashes: -e '/ /' or provide a valid pattern.

error SyntaxError: Unexpected token 'u' in JSON at position 0 ↓

cause Using --compat or --optimize on an unsupported regex, producing non-JSON output.

fix

Ensure the regex is valid and pattern is enclosed in slashes.

Warnings

gotcha The expression must be wrapped in slashes and quotes, e.g., -e '/[a-z]/i'. Omitting slashes will cause parse failure. ↓

fix Always include slashes: regexp-tree-cli -e '/pattern/flags'

deprecated The --compat option for compat-transpiler may not cover all modern regex features (e.g., lookbehind). ↓

fix Use regexp-tree's compat-transpiler directly for full support.

gotcha CLI output is JSON, but with no newline at end; piping may break scripts expecting trailing newline. ↓

fix Use `--table` output to get formatted tables for NFA/DFA.

Install

npm install regexp-tree-cli

yarn add regexp-tree-cli

pnpm add regexp-tree-cli

Imports

parse
wrong
```
const parse = require('regexp-tree').parse
```
correct
```
import { parse } from 'regexp-tree'
```
regexp-tree is the programmatic backend; this CLI is a thin wrapper. ESM import is standard.
generate
wrong
```
import { generate } from 'regexp-tree-cli'
```
correct
```
import { generate } from 'regexp-tree'
```
generate converts AST back to regex string; available only from regexp-tree

optimize

wrong

import optimize from 'regexp-tree'

correct

import { optimize } from 'regexp-tree'

optimize is a named export, not default

Quickstart

Install CLI globally, parse a regex with location and optimizer output.

npm install -g regexp-tree-cli
regexp-tree-cli -e '/a|b/i' -o -l