The rest of what is being typed, drawn after the cursor — zsh's autosuggestion.

Names before history, and the SHORTEST name first. doc means document far more often than it means the last thing you happened to do to document, and a suggestion that jumps straight to document.title is one you have to delete back to the part you wanted. Once document is taken, history extends it — the two sources hand off rather than compete.

Keywords only where a page name did not match and at least three characters are in — so con still finishes as console rather than const, and a lone d is not delete.

Returns only the REMAINDER, so a caller can render it after the cursor without measuring anything. Empty when nothing matches, when the line is empty, or when the only match is what is already typed — suggesting that is noise.

import { suggest } from './suggest.ts';

suggest('doc', { names: ['document', 'documentPictureInPicture'] }); // 'ument'
suggest('doc', { history: ['document.title'] }); // 'ument.title' — nothing better on offer
suggest('document', { names: ['document'], history: ['document.title'] }); // '.title'
suggest('', { history: ['anything'] }); // '' — an empty line suggests nothing