J'ai trouvé un moyen de le faire fonctionner avec des objets qui ont des références cycliques.
Faisons un objet avec des références cycliques.
obj = {
L: {
L: { v: 'lorem' },
R: { v: 'ipsum' }
},
R: {
L: { v: 'dolor' },
R: {
L: { v: 'sit' },
R: { v: 'amet' }
}
}
}
obj.R.L.uncle = obj.L;
obj.R.R.uncle = obj.L;
obj.R.R.L.uncle = obj.R.L;
obj.R.R.R.uncle = obj.R.L;
obj.L.L.uncle = obj.R;
obj.L.R.uncle = obj.R;
Nous ne pouvons pas le faire JSON.stringifyici, à cause des références circulaires.
LOCALSTORAGE.CYCLICJSONa .stringifyet .parsecomme d'habitude JSON, mais fonctionne avec des objets avec des références circulaires. ("Works" signifie parse (stringify (obj)) et obj sont profondément égaux ET ont des ensembles identiques d '"égalités internes")
Mais nous pouvons simplement utiliser les raccourcis:
LOCALSTORAGE.setObject('latinUncles', obj)
recovered = LOCALSTORAGE.getObject('latinUncles')
Ensuite, recoveredsera "le même" à obj, dans le sens suivant:
[
obj.L.L.v === recovered.L.L.v,
obj.L.R.v === recovered.L.R.v,
obj.R.L.v === recovered.R.L.v,
obj.R.R.L.v === recovered.R.R.L.v,
obj.R.R.R.v === recovered.R.R.R.v,
obj.R.L.uncle === obj.L,
obj.R.R.uncle === obj.L,
obj.R.R.L.uncle === obj.R.L,
obj.R.R.R.uncle === obj.R.L,
obj.L.L.uncle === obj.R,
obj.L.R.uncle === obj.R,
recovered.R.L.uncle === recovered.L,
recovered.R.R.uncle === recovered.L,
recovered.R.R.L.uncle === recovered.R.L,
recovered.R.R.R.uncle === recovered.R.L,
recovered.L.L.uncle === recovered.R,
recovered.L.R.uncle === recovered.R
]
Voici l'implémentation de LOCALSTORAGE
LOCALSTORAGE = (function(){
"use strict";
var ignore = [Boolean, Date, Number, RegExp, String];
function primitive(item){
if (typeof item === 'object'){
if (item === null) { return true; }
for (var i=0; i<ignore.length; i++){
if (item instanceof ignore[i]) { return true; }
}
return false;
} else {
return true;
}
}
function infant(value){
return Array.isArray(value) ? [] : {};
}
function decycleIntoForest(object, replacer) {
if (typeof replacer !== 'function'){
replacer = function(x){ return x; }
}
object = replacer(object);
if (primitive(object)) return object;
var objects = [object];
var forest = [infant(object)];
var bucket = new WeakMap(); // bucket = inverse of objects
bucket.set(object, 0);
function addToBucket(obj){
var result = objects.length;
objects.push(obj);
bucket.set(obj, result);
return result;
}
function isInBucket(obj){ return bucket.has(obj); }
function processNode(source, target){
Object.keys(source).forEach(function(key){
var value = replacer(source[key]);
if (primitive(value)){
target[key] = {value: value};
} else {
var ptr;
if (isInBucket(value)){
ptr = bucket.get(value);
} else {
ptr = addToBucket(value);
var newTree = infant(value);
forest.push(newTree);
processNode(value, newTree);
}
target[key] = {pointer: ptr};
}
});
}
processNode(object, forest[0]);
return forest;
};
function deForestIntoCycle(forest) {
var objects = [];
var objectRequested = [];
var todo = [];
function processTree(idx) {
if (idx in objects) return objects[idx];
if (objectRequested[idx]) return null;
objectRequested[idx] = true;
var tree = forest[idx];
var node = Array.isArray(tree) ? [] : {};
for (var key in tree) {
var o = tree[key];
if ('pointer' in o) {
var ptr = o.pointer;
var value = processTree(ptr);
if (value === null) {
todo.push({
node: node,
key: key,
idx: ptr
});
} else {
node[key] = value;
}
} else {
if ('value' in o) {
node[key] = o.value;
} else {
throw new Error('unexpected')
}
}
}
objects[idx] = node;
return node;
}
var result = processTree(0);
for (var i = 0; i < todo.length; i++) {
var item = todo[i];
item.node[item.key] = objects[item.idx];
}
return result;
};
var console = {
log: function(x){
var the = document.getElementById('the');
the.textContent = the.textContent + '\n' + x;
},
delimiter: function(){
var the = document.getElementById('the');
the.textContent = the.textContent +
'\n*******************************************';
}
}
function logCyclicObjectToConsole(root) {
var cycleFree = decycleIntoForest(root);
var shown = cycleFree.map(function(tree, idx) {
return false;
});
var indentIncrement = 4;
function showItem(nodeSlot, indent, label) {
var leadingSpaces = ' '.repeat(indent);
var leadingSpacesPlus = ' '.repeat(indent + indentIncrement);
if (shown[nodeSlot]) {
console.log(leadingSpaces + label + ' ... see above (object #' + nodeSlot + ')');
} else {
console.log(leadingSpaces + label + ' object#' + nodeSlot);
var tree = cycleFree[nodeSlot];
shown[nodeSlot] = true;
Object.keys(tree).forEach(function(key) {
var entry = tree[key];
if ('value' in entry) {
console.log(leadingSpacesPlus + key + ": " + entry.value);
} else {
if ('pointer' in entry) {
showItem(entry.pointer, indent + indentIncrement, key);
}
}
});
}
}
console.delimiter();
showItem(0, 0, 'root');
};
function stringify(obj){
return JSON.stringify(decycleIntoForest(obj));
}
function parse(str){
return deForestIntoCycle(JSON.parse(str));
}
var CYCLICJSON = {
decycleIntoForest: decycleIntoForest,
deForestIntoCycle : deForestIntoCycle,
logCyclicObjectToConsole: logCyclicObjectToConsole,
stringify : stringify,
parse : parse
}
function setObject(name, object){
var str = stringify(object);
localStorage.setItem(name, str);
}
function getObject(name){
var str = localStorage.getItem(name);
if (str===null) return null;
return parse(str);
}
return {
CYCLICJSON : CYCLICJSON,
setObject : setObject,
getObject : getObject
}
})();
obj = {
L: {
L: { v: 'lorem' },
R: { v: 'ipsum' }
},
R: {
L: { v: 'dolor' },
R: {
L: { v: 'sit' },
R: { v: 'amet' }
}
}
}
obj.R.L.uncle = obj.L;
obj.R.R.uncle = obj.L;
obj.R.R.L.uncle = obj.R.L;
obj.R.R.R.uncle = obj.R.L;
obj.L.L.uncle = obj.R;
obj.L.R.uncle = obj.R;
// LOCALSTORAGE.setObject('latinUncles', obj)
// recovered = LOCALSTORAGE.getObject('latinUncles')
// localStorage not available inside fiddle ):
LOCALSTORAGE.CYCLICJSON.logCyclicObjectToConsole(obj)
putIntoLS = LOCALSTORAGE.CYCLICJSON.stringify(obj);
recovered = LOCALSTORAGE.CYCLICJSON.parse(putIntoLS);
LOCALSTORAGE.CYCLICJSON.logCyclicObjectToConsole(recovered);
var the = document.getElementById('the');
the.textContent = the.textContent + '\n\n' +
JSON.stringify(
[
obj.L.L.v === recovered.L.L.v,
obj.L.R.v === recovered.L.R.v,
obj.R.L.v === recovered.R.L.v,
obj.R.R.L.v === recovered.R.R.L.v,
obj.R.R.R.v === recovered.R.R.R.v,
obj.R.L.uncle === obj.L,
obj.R.R.uncle === obj.L,
obj.R.R.L.uncle === obj.R.L,
obj.R.R.R.uncle === obj.R.L,
obj.L.L.uncle === obj.R,
obj.L.R.uncle === obj.R,
recovered.R.L.uncle === recovered.L,
recovered.R.R.uncle === recovered.L,
recovered.R.R.L.uncle === recovered.R.L,
recovered.R.R.R.uncle === recovered.R.L,
recovered.L.L.uncle === recovered.R,
recovered.L.R.uncle === recovered.R
]
)
<pre id='the'></pre>
