// The client-side selection pipeline: pure reducers over the received schema
// tables (config exclusions are already applied server-side). Filter and focus
// are the same operation with different predicates and compose freely ? both
// return a subset that feeds the same MermaidDefinitionGenerator, with no
// server refetch (see docs/DECISIONS.md ? "Table selection").
/**
* Text search over table names. An empty/whitespace query returns every table.
*
* @param {Array<{name: string}>} tables
* @param {string} query
* @returns {Array} the matching subset
*/
export function filterTables(tables, query) {
const needle = String(query ?? '').trim().toLowerCase();
if (needle === '') {
return [...tables];
}
return tables.filter((table) => table.name.toLowerCase().includes(needle));
}
/**
* A table plus its foreign-key neighbours out to `depth` hops. Neighbours are
* followed in both directions ? a table's own FKs (children ? parents) and any
* table that references it (parents ? children) ? so the neighbourhood is the
* connected diagram around the root, not just its outbound edges.
*
* @param {Array} tables the full received set
* @param {string} rootName the focused table
* @param {number} [depth=1]
* @returns {Array} the subset in the neighbourhood (empty if root is unknown)
*/
export function focusTables(tables, rootName, depth = 1) {
const byName = new Map(tables.map((table) => [table.name, table]));
if (!byName.has(rootName)) {
return [];
}
// Undirected adjacency built from every foreign key.
const neighbours = new Map(tables.map((table) => [table.name, new Set()]));
const link = (a, b) => {
if (neighbours.has(a) && neighbours.has(b)) {
neighbours.get(a).add(b);
neighbours.get(b).add(a);
}
};
for (const table of tables) {
for (const fk of table.foreign_keys ?? []) {
if (fk.references_table !== table.name) {
link(table.name, fk.references_table);
}
}
}
// Breadth-first out to `depth` hops.
const visited = new Set([rootName]);
let frontier = [rootName];
for (let hop = 0; hop < depth; hop += 1) {
const next = [];
for (const name of frontier) {
for (const adj of neighbours.get(name) ?? []) {
if (!visited.has(adj)) {
visited.add(adj);
next.push(adj);
}
}
}
if (next.length === 0) {
break;
}
frontier = next;
}
return tables.filter((table) => visited.has(table.name));
}
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