Duplicated backslashes in regular expressions

[PepijnSenders]

Found this issue while trying to get the babili-webpack-plugin to work with date-fns.

The issue is the following, when using the date-fns/format function the formatting regular expression will get messed up.

This code:

var formattingTokensRegExp = new RegExp(
    '(\\[[^\\[]*\\])|(\\\\)?' + '(' + formattingTokens.join('|') + '|.)', 'g'
  )

Will become:

j=new RegExp('(\\\\[[^\\\\[]*\\\\])|(\\\\\\\\)?('+h.join('|')+'|.)','g')

As you can probably see this will result in too many slashes and subsequently break the date-fns/format function.

Wondering if anyone else found this issue before and if it's something persistent if someone could fix it.

For testing this was my .babelrc:

{
    "presets": ["es2015"]
}

My webpack.config.js:

const fs = require('fs');
const path = require('path');

const BabiliPlugin = require('babili-webpack-plugin');
const HtmlWebpackPlugin = require('html-webpack-plugin');

const babelConfig = JSON.parse(fs.readFileSync(path.join(__dirname, '.babelrc')));

module.exports = {
    entry: {
        main: path.join(__dirname, 'src', 'index.js')
    },
    module: {
        rules: [{
            test: /\.js$/,
            loader: 'babel-loader',
            query: babelConfig,
            include: [path.join(__dirname, 'src')],
        }],
    },
    plugins: [
        new BabiliPlugin(),
        new HtmlWebpackPlugin(),
    ],
    output: {
        filename: 'bundle.js'
    }
};

And the file to compile:

import format from 'date-fns/format';

(() => {
    format(new Date(), 'GGGG-[W]WW');
})();

[PepijnSenders]

Btw if someone runs into the same issue, a temporary fix is:

import format from 'date-fns/format';
import enLocale from 'date-fns/locale/en';


(() => {
    console.log(format(new Date(), 'GGGG-[W]WW', {
        locale: {
            format: {
                formatters: enLocale.format.formatters,
                formattingTokensRegExp: /(\[[^\[]*\])|(\\)?(x|ss|s|mm|m|hh|h|do|dddd|ddd|dd|d|aa|a|ZZ|Z|YYYY|YY|X|Wo|WW|W|SSS|SS|S|Qo|Q|Mo|MMMM|MMM|MM|M|HH|H|GGGG|GG|E|Do|DDDo|DDDD|DDD|DD|D|A|.)/g
            }
        }
    }));
})();

[PepijnSenders]

Also by the way the expected output of the console.log is: 2017-W20. Currently it is 2017-[20]20.

[vigneshshanmugam]

This issue was already fixed in master. This is the output code on master branch

var formattingTokensRegExp = new RegExp('([[^[]*])|(\\)?(' + formattingTokens.join('|') + '|.)', 'g');

PR - #490

[PepijnSenders]

Thanks! Do you know when this will be released?

[vigneshshanmugam]

We are doing some cleanups in the new CLI, pretty soon.

[boopathi]

Closing this as it is fixed in master.