0.9.1-alpha.57

Patch Changes

• c34831d: feat(list): ListGroup — the sectioned list

  The settings screen: sections side by side, each under what its rows have in common, with the sentence underneath that says what the switch actually does.

  It is a group of Lists, not a List with headings in it. A list draws its container and its separators between its own children, so a heading placed among the rows would get a hairline above and below it and would sit inside the card it names. Sections are containers side by side, and a heading belongs outside them.

  ListGroup.Section exists because proximity is the only thing grouping a header with its list — nothing draws a box around a section. One gap on the group would put a heading exactly as far from its own rows as from the section above it, so there are two gaps, on the two roots that own them (R4). That ratio is the whole design.

  The header is inset by the row's own padding, read off the List's size table rather than guessed, so the heading and the text it heads share a left edge; the footer is inset with it. ListGroup.Header carries accessibilityRole="header", which is what lets a screen reader jump between sections. The footer carries none — a footnote is prose.

  variant, size, radius, color and hasSeparator are handed down as defaults, and a list that names its own wins: a settings screen is uniform, and setting variant on five lists is five chances to set it differently. isDisabled is the one that is not a default. A List outside any group is unchanged; hasSeparator loses its literal default so that an unset prop can still reach the group's.

  Nothing is walked and nothing is counted: the group publishes two gaps and a type scale, the sections are ordinary children, and one can be built out of something that is not a list.

  For the record, since the name is theirs: The reference implementation's ListGroup is our List — a Surface container with Item · ItemPrefix · ItemContent · ItemTitle · ItemDescription · ItemSuffix, slot for slot. What ships here under that name is the thing neither of us had.