const regex = /(\[trx[^\]]+.)|(\[\/trx[^\]]+.)|(<a[^>]+.)|(<img[^>]+.)(<[^>]+.)/g;
// Alternative syntax using RegExp constructor
// const regex = new RegExp('(\\[trx[^\\]]+.)|(\\[\\\/trx[^\\]]+.)|(<a[^>]+.)|(<img[^>]+.)(<[^>]+.)', 'g')
const str = `[trx_columns autoheight="no" indentation="yes" count="2"][trx_column_item width="40%"]
<table>
<tbody>
<tr>
<td width="96">Suprafaţa</td>
<td width="96">39 m²</td>
</tr>
<tr>
<td width="96">Bucătărie</td>
<td width="96">9,2 m²</td>
</tr>
<tr>
<td width="96">Odaie</td>
<td width="96">19.3 m²</td>
</tr>
<tr>
<td width="96">Antreu</td>
<td width="96">4.3 m²</td>
</tr>
<tr>
<td width="96">Bloc sanitar</td>
<td width="96">3.3 m²</td>
</tr>
<tr>
<td width="96">Balcon</td>
<td width="96">2.9 m²</td>
</tr>
<tr>
<td width="96"><strong>Preţ total</strong></td>
<td width="96"><strong>20 475 €</strong></td>
</tr>
</tbody>
</table>
[/trx_column_item][trx_column_item ]<a href="http://teatral.md/wp-content/uploads/2015/08/39.jpg"><img class="alignnone size-medium wp-image-4147" src="http://teatral.md/wp-content/uploads/2015/08/39-225x300.jpg" alt="39" width="225" height="300" /></a>[/trx_column_item][/trx_columns]`;
const subst = ``;
// The substituted value will be contained in the result variable
const result = str.replace(regex, subst);
console.log('Substitution result: ', result);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for JavaScript, please visit: https://developer.mozilla.org/en/docs/Web/JavaScript/Guide/Regular_Expressions