semantic-network
Version:
A utility library for manipulating a list of links that form a semantic interface to a network of resources.
156 lines • 7.15 kB
JavaScript
import { instanceOfLinkedRepresentation, instanceOfLinkSelector, LinkUtil, } from 'semantic-link';
import { SparseRepresentationFactory } from '../representation/sparseRepresentationFactory';
import { LinkRelation } from '../linkRelation';
import anylogger from 'anylogger';
import { NamedRepresentationFactory } from '../representation/namedRepresentationFactory';
import { instanceOfCollection } from './instanceOf/instanceOfCollection';
const log = anylogger('RepresentationUtil');
export class RepresentationUtil {
/**
* Return the list of keys as a typed array from a representation.
*
* see https://fettblog.eu/typescript-better-object-keys/
* see https://stackoverflow.com/questions/52856496/typescript-object-keys-return-string
*
* @param representation representation object
* @returns array of all the field property keys
*/
static properties(representation) {
return Object.keys(representation)
.filter(x => x !== 'links');
}
static getProperty(o, propertyName) {
return o[propertyName];
}
/**
* Finds (by OR) a resource item in a collection identified through a found link relation or resource attribute
* that matches an item in the collection items.
*
* It looks for items:
*
* 1. matching link relation (default: Self) by uri
* 2. field attribute (default: name ({@link TrackedRepresentationFactory.mappedTitleAttributeName}) on a resource by string
* 3. link selector
*
*/
static findInCollection(collection, options) {
if (!collection || !instanceOfCollection(collection)) {
log.error(`find resource in collection: failed — not an instance of collection '${LinkUtil.getUri(collection, LinkRelation.Self)}'`);
return undefined;
}
const { rel = undefined, where = undefined } = Object.assign({}, options);
let resourceIdentifier;
if (typeof where === 'string' /* Uri */) {
// treat predicate as Uri
resourceIdentifier = where;
}
else if (instanceOfLinkedRepresentation(where)) {
const uri = LinkUtil.getUri(where, rel || LinkRelation.Self);
if (uri) {
resourceIdentifier = uri;
}
else {
log.debug('find resource in collection: not found — no \'where\' and \'rel\' options that combine to create resource identifier on \'%s\'', rel || LinkRelation.Self, LinkUtil.getUri(collection, LinkRelation.Self));
return undefined;
}
}
else if (instanceOfLinkSelector(where)) {
const uri = LinkUtil.getUri(collection, where);
if (uri) {
resourceIdentifier = uri;
}
else {
log.debug('find resource in collection: not found — no \'where\' and link selector \'%o\' options that combine to create resource identifier on \'%s\'', where, LinkUtil.getUri(collection, LinkRelation.Self));
return undefined;
}
}
else if (Array.isArray(where)) {
log.debug('find resource in collection: array cannot be assigned to where');
}
else if (!where) {
log.debug('find resource in collection: where not used as \'%s\'', where);
}
else {
log.debug('find resource in collection: unknown where');
}
// attribute look up strategy. Used for fallback strategy 2.
// TODO: allow for multiple link relations in underlying function
const name = NamedRepresentationFactory.defaultNameStrategy(rel);
// title will only exist where a resource is passed in AND there is a mapped title. Used for fallback strategy 3.
const mappedTitleAttributeName = SparseRepresentationFactory.defaultMappedTitleAttributeName;
/** internal helper function to return comparable string from the property of a resource */
function getResourceTitle(obj, prop = mappedTitleAttributeName) {
var _a;
return (_a = obj === null || obj === void 0 ? void 0 : obj[prop]) === null || _a === void 0 ? void 0 : _a.toLowerCase();
}
const resourceTitle = getResourceTitle(where);
log.debug('find resource in collection: \'%s\' \'%s\'', name, resourceTitle);
// go through the collection and match the URI against either a link relation or attribute
return collection
.items
.find(item =>
// strategy 1 & 4: Self link of item matches
LinkUtil.getUri(item, rel || LinkRelation.Self) === resourceIdentifier ||
// strategy 2: the attribute on the resource is a uri that matches
(name && getResourceTitle(item, name) === resourceIdentifier) ||
// strategy 3: fallback to mapped title values matching (not uris but titles)
(resourceTitle && getResourceTitle(item) === resourceTitle));
}
static fields(representation) {
return Object.keys(representation)
.filter(x => x !== 'links');
}
/**
* Removes the item from the collection by matching its Self link. If not found, it returns undefined.
*/
static removeItemFromCollection(collection, item) {
const resourceUri = LinkUtil.getUri(item, LinkRelation.Self);
const indexOfItemToBeRemoved = collection.items.findIndex(item => LinkUtil.getUri(item, LinkRelation.Self) === resourceUri);
if (indexOfItemToBeRemoved >= 0) {
// eslint-disable-next-line @typescript-eslint/no-unused-vars
const [head, _] = collection.items.splice(indexOfItemToBeRemoved, 1);
return head;
}
return undefined;
}
/**
* Removes the item from the collection by matching its Self link. If not found, returns undefined.
*/
static appendItemToCollection(collection, item) {
if (collection.items) {
collection.items.splice(collection.items.length, 0, item);
}
else {
log.warn('Collection adding new items array, reactive bindings may fail');
collection.items = [item];
}
return collection;
}
static prependItemToCollection(collection, item) {
if (collection.items) {
collection.items.unshift(item);
}
else {
log.warn('Collection adding new items array, reactive bindings may fail');
collection.items = [item];
}
return collection;
}
/**
* Returns the first item from a collection
*
* @obsolete this should never be used but rather look for the 'current' on links and return resource
*/
static current(collection) {
if (!collection) {
return undefined;
}
if (instanceOfCollection(collection)) {
// eslint-disable-next-line @typescript-eslint/no-unused-vars
const [head] = collection.items;
return head;
}
return undefined;
}
}
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