public static TagHelperAttributeList AddOrAppendAttribute(
this TagHelperAttributeList tagAttributesList,
string name,
string attrValue,
bool appendFirst = false,
bool checkForDuplicates = false,
Func <string, bool> dontAddIfPred = null)
{
if (name.IsNulle())
{
throw new ArgumentNullException();
}
if (tagAttributesList == null)
{
throw new ArgumentNullException();
}
if (attrValue == null)
{
return(tagAttributesList);
}
TagHelperAttribute attr = tagAttributesList.IsNulle()
? null
: tagAttributesList.FirstN(t => t.Name == name);
if (attr != null)
{
string attrValStr = attr.Value?.ToString();
if (attrValStr.IsNulle())
{
attr = null;
}
else
{
if (dontAddIfPred != null && dontAddIfPred.Invoke(attrValStr))
{
return(tagAttributesList);
}
attrValue = appendFirst
? $"{attrValue} {attrValStr}"
: $"{attrValStr} {attrValue}";
}
}
attrValue = attrValue.TrimIfNeeded();
if (checkForDuplicates && attr != null)
{
// so only have to do this check if attribute already exists, that single check will GREATLY improv perf, removing a needless case
attrValue = attrValue
.SplitAndRemoveWhiteSpaceEntries(_whiteSpSeparators)
.Distinct()
.JoinToString(" ");
}
tagAttributesList.SetAttribute(name, attrValue);
return(tagAttributesList);
}
