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Avoid stack overflow when comparing objects with cycles (like DOM Elements) #5

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Avoid stack overflow when comparing objects with cycles (like DOM Elements) #5

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a01b09f
avoids stack overflow when comparing objects in the same way jasmine …
jpbochi Aug 9, 2013
b70a338
avoids stack overflow when building diff html for DOM elements
jpbochi Aug 9, 2013
aef38fc
correct toString of functions and DOM elements
jpbochi Aug 9, 2013
35486dd
added option to ignore keys
jpbochi Aug 10, 2013
a647597
considering empty objects of type different than 'object' as different
jpbochi Aug 10, 2013
928a8b4
supporting comparison of null values
jpbochi Aug 12, 2013
11b4935
put limit on inspect of objects to avoid stack overflow
jpbochi Sep 3, 2013
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92 changes: 74 additions & 18 deletions objectDiff.js
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Original file line number Diff line number Diff line change
Expand Up @@ -5,19 +5,28 @@ var objectDiff = typeof exports != 'undefined' ? exports : {};
* @param {Object} b
* @return {Object}
*/
objectDiff.diff = function diff(a, b) {
objectDiff.diff = function diff(a, b, ignore) {

if (a === b) {
return {
changed: 'equal',
value: a
}
}
if (a.__diffComparedTo__ === b && b.__diffComparedTo__ === a) {
return true;
}

var value = {};
var equal = true;
var ignoredKeys = ['__diffComparedTo__'].concat(ignore || []);

a.__diffComparedTo__ = b;
b.__diffComparedTo__ = a;

for (var key in a) {
if (ignoredKeys.indexOf(key) != -1) { continue; }

if (key in b) {
if (a[key] === b[key]) {
value[key] = {
Expand All @@ -28,7 +37,7 @@ objectDiff.diff = function diff(a, b) {
var typeA = typeof a[key];
var typeB = typeof b[key];
if (a[key] && b[key] && (typeA == 'object' || typeA == 'function') && (typeB == 'object' || typeB == 'function')) {
var valueDiff = diff(a[key], b[key]);
var valueDiff = diff(a[key], b[key], ignore);
if (valueDiff.changed == 'equal') {
value[key] = {
changed: 'equal',
Expand Down Expand Up @@ -57,6 +66,8 @@ objectDiff.diff = function diff(a, b) {
}

for (key in b) {
if (ignoredKeys.indexOf(key) != -1) { continue; }

if (!(key in a)) {
equal = false;
value[key] = {
Expand All @@ -66,6 +77,9 @@ objectDiff.diff = function diff(a, b) {
}
}

delete a.__diffComparedTo__;
delete b.__diffComparedTo__;

if (equal) {
return {
changed: 'equal',
Expand All @@ -85,21 +99,33 @@ objectDiff.diff = function diff(a, b) {
* @param {Object} b
* @return {Object}
*/
objectDiff.diffOwnProperties = function diffOwnProperties(a, b) {
objectDiff.diffOwnProperties = function diffOwnProperties(a, b, ignore) {

if (a === b) {
return {
changed: 'equal',
value: a
}
}
if (a && b && a.__diffComparedTo__ === b && b.__diffComparedTo__ === a) {
return true;
}

var diff = {};
var equal = true;
var keys = Object.keys(a);
var typeofA = typeof a;
var typeofB = typeof b;
var keys = [];
var ignoredKeys = ['__diffComparedTo__'].concat(ignore || []);

if (a && typeofA === 'object') { keys = Object.keys(a); }
if (a) { a.__diffComparedTo__ = b; }
if (b) { b.__diffComparedTo__ = a; }

for (var i = 0, length = keys.length; i < length; i++) {
var key = keys[i];
if (ignoredKeys.indexOf(key) != -1) { continue; }

if (b.hasOwnProperty(key)) {
if (a[key] === b[key]) {
diff[key] = {
Expand All @@ -110,7 +136,7 @@ objectDiff.diffOwnProperties = function diffOwnProperties(a, b) {
var typeA = typeof a[key];
var typeB = typeof b[key];
if (a[key] && b[key] && (typeA == 'object' || typeA == 'function') && (typeB == 'object' || typeB == 'function')) {
var valueDiff = diffOwnProperties(a[key], b[key]);
var valueDiff = diffOwnProperties(a[key], b[key], ignore);
if (valueDiff.changed == 'equal') {
diff[key] = {
changed: 'equal',
Expand Down Expand Up @@ -138,10 +164,13 @@ objectDiff.diffOwnProperties = function diffOwnProperties(a, b) {
}
}

keys = Object.keys(b);
keys = [];
if (b && typeofB === 'object') { keys = Object.keys(b); }

for (i = 0, length = keys.length; i < length; i++) {
key = keys[i];
if (ignoredKeys.indexOf(key) != -1) { continue; }

if (!a.hasOwnProperty(key)) {
equal = false;
diff[key] = {
Expand All @@ -151,11 +180,20 @@ objectDiff.diffOwnProperties = function diffOwnProperties(a, b) {
}
}

if (equal) {
if (a) { delete a.__diffComparedTo__; }
if (b) { delete b.__diffComparedTo__; }

if (equal && (typeofA === typeofB) && (typeofA === 'object')) {
return {
value: a,
changed: 'equal'
}
} else if (equal) {
return {
changed: 'primitive change',
removed: a,
added: b
}
} else {
return {
changed: 'object change',
Expand All @@ -177,6 +215,14 @@ objectDiff.diffOwnProperties = function diffOwnProperties(a, b) {
var diff = changes.value;
if (changes.changed == 'equal') {
return inspect(diff);
} else if (changes.changed == 'primitive change') {
return [
'<div class="diff-level">',
'<del class="diff diff-key">', inspect(changes.removed), '</del>',
'<span>,</span>\n',
'<ins class="diff diff-key">', inspect(changes.added), '</ins>',
'</div>'
].join('');
}

for (var key in diff) {
Expand Down Expand Up @@ -215,9 +261,7 @@ objectDiff.diffOwnProperties = function diffOwnProperties(a, b) {
* @return {string}
*/
function stringifyObjectKey(key) {
return /^[a-z0-9_$]*$/i.test(key) ?
key :
JSON.stringify(key);
return /^[a-z0-9_$]*$/i.test(key) ? key : JSON.stringify(key);
}

/**
Expand All @@ -242,7 +286,8 @@ objectDiff.diffOwnProperties = function diffOwnProperties(a, b) {
* @see http://jsperf.com/continuation-passing-style/3
* @return {string}
*/
function _inspect(accumulator, obj) {
function _inspect(accumulator, obj, deep) {
deep = deep || 0;
switch(typeof obj) {
case 'object':
if (!obj) {
Expand All @@ -253,23 +298,34 @@ objectDiff.diffOwnProperties = function diffOwnProperties(a, b) {
var length = keys.length;
if (length === 0) {
accumulator += '<span>{}</span>';
} else if (obj.nodeType > 0) {
accumulator += '<span>' + Object.prototype.toString.call(obj) + '</span>';
} else {
accumulator += '<span>{</span>\n<div class="diff-level">';
for (var i = 0; i < length; i++) {
var key = keys[i];
accumulator = _inspect(accumulator + stringifyObjectKey(escapeHTML(key)) + '<span>: </span>', obj[key]);
if (i < length - 1) {
accumulator += '<span>,</span>\n';
deep += 1;
if (deep > 3) {
accumulator += '<span>[too deep...]</span>';
} else {
accumulator += '<span>{</span>\n<div class="diff-level">';
for (var i = 0; i < length; i++) {
var key = keys[i];
accumulator = _inspect(accumulator + stringifyObjectKey(escapeHTML(key)) + '<span>: </span>', obj[key], deep);
if (i < length - 1) {
accumulator += '<span>,</span>\n';
}
}
accumulator += '\n</div><span>}</span>'
}
accumulator += '\n</div><span>}</span>'
}
break;

case 'string':
accumulator += JSON.stringify(escapeHTML(obj));
break;

case 'function':
accumulator += Object.prototype.toString.call(obj);
break;

case 'undefined':
accumulator += 'undefined';
break;
Expand Down