The Tor Browser / file comparison
comparison: addon-sdk/source/lib/diffpatcher/diff.js
addon-sdk/source/lib/diffpatcher/diff.js
- branch
- TOR_BUG_9701
- changeset 10
- ac0c01689b40
equal
deleted
inserted
replaced
| -1:000000000000 | 0:74af8ae917d8 |
|---|---|
| 1 "use strict"; | |
| 2 | |
| 3 var method = require("../method/core") | |
| 4 | |
| 5 // Method is designed to work with data structures representing application | |
| 6 // state. Calling it with a state should return object representing `delta` | |
| 7 // that has being applied to a previous state to get to a current state. | |
| 8 // | |
| 9 // Example | |
| 10 // | |
| 11 // diff(state) // => { "item-id-1": { title: "some title" } "item-id-2": null } | |
| 12 var diff = method("diff@diffpatcher") | |
| 13 | |
| 14 // diff between `null` / `undefined` to any hash is a hash itself. | |
| 15 diff.define(null, function(from, to) { return to }) | |
| 16 diff.define(undefined, function(from, to) { return to }) | |
| 17 diff.define(Object, function(from, to) { | |
| 18 return calculate(from, to || {}) || {} | |
| 19 }) | |
| 20 | |
| 21 function calculate(from, to) { | |
| 22 var diff = {} | |
| 23 var changes = 0 | |
| 24 Object.keys(from).forEach(function(key) { | |
| 25 changes = changes + 1 | |
| 26 if (!(key in to) && from[key] != null) diff[key] = null | |
| 27 else changes = changes - 1 | |
| 28 }) | |
| 29 Object.keys(to).forEach(function(key) { | |
| 30 changes = changes + 1 | |
| 31 var previous = from[key] | |
| 32 var current = to[key] | |
| 33 if (previous === current) return (changes = changes - 1) | |
| 34 if (typeof(current) !== "object") return diff[key] = current | |
| 35 if (typeof(previous) !== "object") return diff[key] = current | |
| 36 var delta = calculate(previous, current) | |
| 37 if (delta) diff[key] = delta | |
| 38 else changes = changes - 1 | |
| 39 }) | |
| 40 return changes ? diff : null | |
| 41 } | |
| 42 | |
| 43 diff.calculate = calculate | |
| 44 | |
| 45 module.exports = diff |
