@directus/api/dist/permissions/modules/process-ast/utils/dedupe-access.js

Directus is a real-time API and App dashboard for managing SQL database content

import hash from 'object-hash';
/**
 * Deduplicate the permissions sets by merging the field sets based on the access control rules
 * (`permissions` in Permission rows)
 *
 * This allows the cases injection to be more efficient by not having to generate duplicate
 * case/when clauses for permission sets where the rule access is identical
 */
export function dedupeAccess(permissions) {
    // Map of `ruleHash: fields[]`
    const map = new Map();
    for (const permission of permissions) {
        const rule = permission.permissions ?? {};
        // Two JS objects can't be equality checked. Object-hash will resort any nested arrays
        // deterministically meaning that this can be used to compare two rule sets where the array
        // order does not matter
        const ruleHash = hash(rule, {
            algorithm: 'passthrough',
            unorderedArrays: true,
        });
        if (map.has(ruleHash) === false) {
            map.set(ruleHash, { rule, fields: new Set() });
        }
        const info = map.get(ruleHash);
        for (const field of permission.fields ?? []) {
            info.fields.add(field);
        }
    }
    return Array.from(map.values());
}