/
decycle.js
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/
decycle.js
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// Modified version of https://github.com/douglascrockford/JSON-js/blob/master/cycle.js
// Handle DOM elements
// Removed global reference
// Stop traversing beyond a max depth
/*
cycle.js
2013-02-19
Public Domain.
NO WARRANTY EXPRESSED OR IMPLIED. USE AT YOUR OWN RISK.
This code should be minified before deployment.
See http://javascript.crockford.com/jsmin.html
USE YOUR OWN COPY. IT IS EXTREMELY UNWISE TO LOAD CODE FROM SERVERS YOU DO
NOT CONTROL.
*/
/*jslint evil: true, regexp: true */
/*members $ref, apply, call, decycle, hasOwnProperty, length, prototype, push,
retrocycle, stringify, test, toString, nodeType
*/
/* exported decycle */
'use strict';
function decycle(object, maxDepth) {
// Make a deep copy of an object or array, assuring that there is at most
// one instance of each object or array in the resulting structure. The
// duplicate references (which might be forming cycles) are replaced with
// an object of the form
// {$ref: PATH}
// where the PATH is a JSONPath string that locates the first occurance.
// So,
// var a = [];
// a[0] = a;
// return JSON.stringify(JSON.decycle(a));
// produces the string '[{"$ref":"$"}]'.
// JSONPath is used to locate the unique object. $ indicates the top level of
// the object or array. [NUMBER] or [STRING] indicates a child member or
// property.
var objects = []; // Keep a reference to each unique object or array
var paths = []; // Keep the path to each unique object or array
maxDepth = maxDepth || 5;
return (function derez(value, path, depth) {
if (depth > maxDepth) {
return 'Decycle max depth reached at ' + maxDepth + '. You may override the default by setting "client_decycle_depth" in your testem config.';
}
// The derez recurses through the object, producing the deep copy.
var i, // The loop counter
name, // Property name
nu; // The new object or array
// typeof null === 'object', so go on if this value is really an object but not
// one of the weird builtin objects.
// Handle DOM elements
if (value === null || typeof value === 'undefined' || value instanceof Boolean || value instanceof Number) {
return value;
}
if (typeof value === 'object' && typeof value.nodeType === 'number') {
return String(value);
}
if (typeof value === 'object' && value !== null &&
!(value instanceof Date) &&
!(value instanceof RegExp) &&
!(value instanceof String)) {
// If the value is an object or array, look to see if we have already
// encountered it. If so, return a $ref/path object. This is a hard way,
// linear search that will get slower as the number of unique objects grows.
for (i = 0; i < objects.length; i += 1) {
if (objects[i] === value) {
return {$ref: paths[i]};
}
}
// Otherwise, accumulate the unique value and its path.
objects.push(value);
paths.push(path);
// If it is an array, replicate the array.
if (Object.prototype.toString.apply(value) === '[object Array]') {
nu = [];
for (i = 0; i < value.length; i += 1) {
nu[i] = derez(value[i], path + '[' + i + ']', depth + 1);
}
} else {
// If it is an object, replicate the object.
nu = {};
for (name in value) {
if (Object.prototype.hasOwnProperty.call(value, name)) {
nu[name] = derez(value[name],
path + '[' + JSON.stringify(name) + ']', depth + 1);
}
}
}
return nu;
}
return value;
}(object, '$', 0));
}