const regex = /^<!--(?!\[[^]+])(?:(?!-->).)*-->$/gsm;
// Alternative syntax using RegExp constructor
// const regex = new RegExp('^<!--(?!\\[[^]+])(?:(?!-->).)*-->$', 'gsm')
const str = `<!-- some comments 1 -->
<!-- 1.91 -->
<!--
//-->
<!-- -->
<!--[if IE]> <![endif]-->
<!--[if !IE]><!--> <!--<![endif]-->
<!--[if IE 6]> <![endif]-->
<!--[if lte IE 6]><html class="ie6 no-js">
<!--[if gt IE 8]><!--><html class="no-js"><!--<![endif]-->
<!--[if IE]>
<meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1">
<![endif]-->`;
// Reset `lastIndex` if this regex is defined globally
// regex.lastIndex = 0;
let m;
while ((m = regex.exec(str)) !== null) {
// This is necessary to avoid infinite loops with zero-width matches
if (m.index === regex.lastIndex) {
regex.lastIndex++;
}
// The result can be accessed through the `m`-variable.
m.forEach((match, groupIndex) => {
console.log(`Found match, group ${groupIndex}: ${match}`);
});
}
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