Function _createPersistentIds

src/core/runtime/morph.js:227–240

(oldIdElements, newIdElements)

}

function _createPersistentIds(oldIdElements, newIdElements) {
    var duplicateIds = new Set(), oldIdTagNameMap = new Map();
    for (var { id, tagName } of oldIdElements) {
        if (oldIdTagNameMap.has(id)) duplicateIds.add(id);
        else if (id) oldIdTagNameMap.set(id, tagName);
    }
    var persistentIds = new Set();
    for (var { id, tagName } of newIdElements) {
        if (persistentIds.has(id)) duplicateIds.add(id);
        else if (oldIdTagNameMap.get(id) === tagName) persistentIds.add(id);
    }
    for (var id of duplicateIds) persistentIds.delete(id);
    return persistentIds;
}

function _populateIdMapWithTree(idMap, persistentIds, root, elements) {
    for (var elt of elements) {