@yubiuser

I think the new parse function will solve some issues, like when "infinite" was considered as hostname (Example: aa:bb:cc:dd:ee:ff, 192.168.0.2, infinite). Now "infinite" is always considered as a lease time string (like on dnsmasq code).

Also, now the position of the items are not really important. The function will parse them and, if valid, will show them on the table, in the correct columns.

This pull request has conflicts, please resolve those before we can evaluate the pull request.

Conflicts have been resolved.

The current user interface looks like this:

During testing, I found one edge-case:

Note: you will need to have at least one active lease (so the copy button is visible) and at least one static lease.

1. Click a static-table cell and type a change (Save/Cancel buttons appear, textarea greys out).
2. Without clicking Save, click "Copy to static leases" in the active lease table above.
3. Table redraws causing the edit to be gone with no warning (Save button/hint vanish too).

Further:

• Lease-time-shaped hostname makes the line uneditable (in theory, 5m is a valid hostname)
• Colon-bearing values misclassified as a MAC (like fe80::1,host or tag:green,192.168.1.5) and validateMAC fails so the line cannot be saved

I know that the latter two existed is my initial draft, too, and I am fine with having them as we-can't-fix-'em-all.

I added a proposed fix for the issue I found. I force-pushed as I broke the tests

scripts/js/settings-dhcp.js:533:3                                                                                                 
    ✖  533:3  Expected blank line before this statement.  @stylistic/padding-line-between-statements                                                      
                                                                                                                                                          
    1 error

Should go through clear now. I will approve this but please have a look at my commit before merging.

but please have a look at my commit before merging.

Commit checked. I think this is fine.
We can improve/polish the "Copy to static leases" behavior in a follow up PR, if needed.

Further:

• Lease-time-shaped hostname makes the line uneditable (in theory, 5m is a valid hostname)

I agree that 5m is both: a valid hostname and a lease time string, but I think dnsmasq considers it as a time lease when dhcp-host=00:11:22:33:44:55,10.0.0.1,5m is added to a config file (maybe I'm wrong).

• Colon-bearing values misclassified as a MAC (like fe80::1,host or tag:green,192.168.1.5) and validateMAC fails so the line cannot be saved

Hmm... we need more work to check/validate the fe80::1,host case.
In any case, this value can still be saved if you type it on the textarea and then click on the "Save & Apply" button (even if the table misidentify it as an invalid MAC or invalid IP).

The other case (tag:green,192.168.1.5), is correctly handled:

• if you type tag:green,192.168.1.5 on the textarea, this line will be correctly considered an Advanced line (the line will be saved using the "Save & Apply" button).
• if you try to type tag:green on the MAC Address column, the validation function will correctly identify it as an invalid MAC (the line won't be saved, as expected).