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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this file,
"use strict";
const {
actions,
viewState,
const handlers = Object.create(null);
handlers[actions.POP_VIEW] = function (view, _) {
assert(view.previous, "Had better have a previous view state when POP_VIEW");
return Object.freeze({
state: view.previous.state,
previous: null,
});
};
handlers[actions.CHANGE_VIEW] = function (view, action) {
const { newViewState, oldDiffing, oldSelected } = action;
assert(newViewState);
if (newViewState === viewState.INDIVIDUALS) {
assert(oldDiffing || oldSelected);
return Object.freeze({
state: newViewState,
previous: Object.freeze({
state: view.state,
selected: oldSelected,
diffing: oldDiffing,
}),
});
}
return Object.freeze({
state: newViewState,
previous: null,
});
};
const DEFAULT_VIEW = {
state: viewState.TREE_MAP,
previous: null,
};
module.exports = function (view = DEFAULT_VIEW, action) {
const handler = handlers[action.type];
return handler ? handler(view, action) : view;
};