Strip certain HTML from string
Solution 1:
You can use the DOMParser API to parse and manipuate the HTML code:
post = '<p><strong><em><u>"Soft fingers began to tap the sill of the car window, and the hard fingers tightened on the restless drawing sticks. In the doorways of the sun-beaten tenant houses, women sighed and then shifted feet so that the one that had been down was now on top, and the toes working. Dogs came sniffing near the owner cars and wetted on all four tires one after another. And chickens lay in the sunny dust and fluffed their feathers </u></em></strong></p><p><br></p><p><br></p><p><br></p><p><br></p><p><br></p><p><br></p><p><br></p><p><br></p><p><br></p><p><br></p><p><br></p><p><br></p><p><br></p><p><strong><em>to get the cleansing dust down to the skin. In the little sties the pigs grunted inquiringly over the muddy remnants of the slops.""Soft fingers began to tap the sill of the car window, and the hard fingers tightened on the restless drawing sticks. In the doorways of the sun-beaten tenant houses, women sighed and then shifted feet so that the one that had been down was now on top, and the toes working. Dogs came sniffing near the owner cars and wetted on all four tires one after another. And chickens lay in the sunny dust and fluffed their feathers to get the cleansing dust down to the skin. In the little sties the pigs grunted inquiringly over the muddy remnants of the slops."</em></strong></p>'
function stripElements(post) {
const doc = new DOMParser().parseFromString(post, 'text/html');
doc.querySelectorAll('body :not(p)').forEach(el => el.replaceWith(el.textContent))
return doc.body.innerHTML;
}
console.log(stripElements(post))Solution 2:
Rule #1: Don't manipulate HTML with regexes. Use a DOM parser instead.
Rule #2: You probably don't want to fuss with the overhead of a DOM parser, just want to get the job done, and are likely to ignore Rule #1.
Therefore, if you wish, something like this might do the trick:
return post.replace(/<\/?[a-z]+>/gi, m => m.toLowerCase() === '<br>' ? '<p></p>' : '');
I'm not exactly sure this is how you wanted to handle the line breaks, but given this as a start you should be able to tweak it as you need.