72 lines
1.9 KiB
JavaScript
72 lines
1.9 KiB
JavaScript
import jsonDiffer from 'fast-json-patch';
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import { cloneDeep } from 'lodash';
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/**
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* converts non-initial history entries into diffs
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*
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* @param {Array} longHistory
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* @returns {Array}
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*/
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export function migrateFromSnapshotsToDiffs(longHistory) {
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return (
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longHistory
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// convert non-initial history entries into diffs
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.map((entry, index) => {
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if (index === 0) {
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return entry;
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}
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return generateHistoryEntry(longHistory[index - 1], entry);
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})
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);
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}
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/**
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* Generates an array of history objects sense the previous state.
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* The object has the keys
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* op (the operation performed),
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* path (the key and if a nested object then each key will be separated with a `/`)
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* value
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* with the first entry having the note and a timestamp when the change took place
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*
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* @param {object} previousState - the previous state of the object
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* @param {object} newState - the update object
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* @param {string} [note] - a optional note for the state change
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* @returns {Array}
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*/
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export function generateHistoryEntry(previousState, newState, note) {
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const entry = jsonDiffer.compare(previousState, newState);
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// Add a note to the first op, since it breaks if we append it to the entry
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if (entry[0]) {
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if (note) {
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entry[0].note = note;
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}
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entry[0].timestamp = Date.now();
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}
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return entry;
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}
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/**
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* Recovers previous txMeta state obj
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*
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* @param _shortHistory
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* @returns {object}
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*/
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export function replayHistory(_shortHistory) {
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const shortHistory = cloneDeep(_shortHistory);
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return shortHistory.reduce(
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(val, entry) => jsonDiffer.applyPatch(val, entry).newDocument,
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);
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}
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/**
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* Snapshot {@code txMeta}
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*
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* @param {object} txMeta - the tx metadata object
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* @returns {object} a deep clone without history
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*/
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export function snapshotFromTxMeta(txMeta) {
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const shallow = { ...txMeta };
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delete shallow.history;
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return cloneDeep(shallow);
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}
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