BlockKind: {
bulletList: "bulletList";
callout: "callout";
code: "code";
embed: "embed";
expand: "expand";
heading: "heading";
image: "image";
infobox: "infobox";
keyValue: "keyValue";
layout: "layout";
layoutColumn: "layoutColumn";
listItem: "listItem";
map: "map";
meter: "meter";
orderedList: "orderedList";
paragraph: "paragraph";
quote: "quote";
resourceCollection: "resourceCollection";
resourceLink: "resourceLink";
rule: "rule";
secret: "secret";
table: "table";
tableCell: "tableCell";
tableRow: "tableRow";
taskItem: "taskItem";
taskList: "taskList";
textField: "textField";
unsupported: "unsupported";
} = ...
Every block kind, as an object of literals. The declaration fails to compile when the spec adds a kind this object lacks.