RE2

Getting Started

Installation

npm i wasm-re2

Usage

import { RE2 } from 'wasm-re2';

const regex = new RE2('(b|^a)', 'g');

const isFound = regex.test('aabc');
// true

const matches = regex.exec('aabc');
// [ ['a', 'a'], ['b', 'b'] ]

API

RE2.test(string)

Executes a search for a match between a regular expression and a specified string.

Returns true or false.

RE2.exec(string)

Returns all matches of the regular expression against a string.

Works like non-iterable RegExp matchAll.

Exec returns all results in a 2D array where each result consists of [fullmatch, ...captureMathces].

Example:

const regex = new RE2('(abc)\\d+(zxc)', 'g');

regex.exec('123abc123zxc123abc123zxc123')
// [ ['abc123zxc', 'abc', 'zxc'], ['abc123zxc', 'abc', 'zxc'] ]

RE2.replace(string, rewrite)

Return a new string with some or all matches of a pattern replaced by a replacement.

RE2.numberOfCaptureGroups()

Returns number of capture groups.

Working with Emscripten

For Mac

If you use mac proceed to Pull submodule google-re2. You need node and python to be installed.

For Windows

Install Debian from Microsoft Store, then launch and create UNIX user.

Enter new UNIX username:
New password:
Retype new password:

Then launch:

sudo apt-get update -y && sudo apt-get install nodejs npm git python -y

Install Subsystem WSL using Setting on Windows 10:

1. Open Settings.
2. Click on Apps.
3. Under the Related settings section, click the Programs and Features option.
4. Click the Turn Windows features on or off option on the left pane.
5. Check the Windows Subsystem for the Linux checkbox.
6. Click the OK button.
7. Then you need to reboot the PC.

Launch IDE with WSL, and do all next actions in WSL Terminal.

Pull submodule google-re2

git submodule update --init

Clone emsdk in your storage of repos

git clone https://github.com/emscripten-core/emsdk.git

Enter that directory

cd emsdk

Fetch the latest version of the emsdk (not needed the first time you clone)

git pull

Download and install the latest SDK tools

./emsdk install latest

Make the "latest" SDK "active" for the current user. (writes ~/.emscripten file)

./emsdk activate latest

Activate PATH and other environment variables in the current terminal

from emsdk dir: source ./emsdk_env.sh

from re2: source ../emsdk/emsdk_env.sh

Compile C code

Install dependencies

npm i

Update/create foundation folder running

npm run foundation

Make sure you have permissions to execute the file chmod +x ./compile.sh

Run script npm run compile

Testing

npm test

Updating re2 to latest

If google-re2 module is updated

git pull --recurse-submodules

Then run this script to update re2 package

npm run build:update

Rollup

To change rollup configuration read Rollup_FAQ.md in yaml-core package or visit https://rollupjs.org/guide/en/.