The delimiter that commits a tag must be stated

What it is

After a word is typed, some key must turn “the string being written” into a chip. That key may be Enter, comma, space, or Tab. When people do not know the rule, they type a comma into the tag, or press Enter and submit the whole form. A tag delimiter convention makes “what commits a chip” visible before typing, and consistent across the product. The issue is how one tag is committed, not whether the vocabulary is dirty, and not whether removing one chip disturbs the others.

Why it happens

The slot holds two modes—“edit the current word” and “commit a chip”—and the delimiter switches them. If the rule lives only in the implementer’s head, people use whatever they learned in another product: some commit on space, some need space inside the word (“interaction design”). Enter usually submits a form; if it also commits a tag, Enter while focus is in the slot can submit by mistake. A Chinese comma is not an ASCII comma; listening only for the latter blocks Chinese users from committing. The convention must be externalized, and must be offset from the form-submit key or must leave focus in the slot after commit.

Where it stops holding

When only one tag is ever added, with a separate Add button, the delimiter is not the main path and the hint can be soft. Pasting a, b, c from the clipboard also uses the delimiter to split; the rule must cover type and paste. If comma is a legal character in a tag (rare), comma cannot also commit. Space and Enter during IME composition commit a syllable, not a tag.

Applying it

• On the idle slot, write how to commit (“comma or Enter makes a tag”); do not make people probe.
• Let Enter inside the slot commit a tag without submitting the form, unless there is no word still being edited.
• Accept both Chinese and ASCII commas; whether space commits depends on multi-word tags and must be written down.
• Verify by asking, without help, “how does this word become a tag.” Then press Enter, comma, a Chinese comma, and space. If an unexpected key submits the form or eats punctuation into the tag, the convention is not yet external.

Related

• Within the group: E2.20.1 Free tagging must handle duplicates and near-spellings · E2.20.3 Each chip must be removable without disturbing the others · E2.20.4 Many tags need a wrapping or stacking layout
• Adjacent: E2.10 Search fields · E2.16 Autocomplete dropdowns
• Search terms: tag delimiter convention · comma to commit · chip token field