This may be obvious to others, but I just spent hours and my feeble brain only caught up to it after a long break.
If you are looping through a string which has multiple substrings that need to be replaced, you have to add an offset factor to each original offset before you replaced any strings. Here is a real world example:
From draft.js we get paragraphs with multiple links designated only with offset, anchor text length, url, target. So each anchor text must be wrapped in the <a href="url" target="target">anchortext</a> to save proper content in the database.
Here is the implementation of offset factor:
$offset_factor = 0;
foreach($content->links->links as $index=>$link){
$replacement = '<a href="'.$link->href.'" target="$link->target">'.$link->anchorText.'</a>';
$new_offset = $link->offset + $offset_factor;
$newtext = \substr_replace($content->text, $replacement, $new_offset, $link->length);
//now we reset the original paragraph text with newtext
$content->text = $newtext;
//calculate the new offset by calculating the difference in replacement length and original length and add that to the offset_factor
$additional_characters = strlen($replacement) - $link->length;
$offset_factor = $offset_factor + $additional_characters;
}
I hope this helps a noobie :) If there is another easier way, I would love to hear about it.
