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Diffstat (limited to 'node_modules/cycle/cycle.js')
-rw-r--r-- | node_modules/cycle/cycle.js | 170 |
1 files changed, 170 insertions, 0 deletions
diff --git a/node_modules/cycle/cycle.js b/node_modules/cycle/cycle.js new file mode 100644 index 0000000..2e776ad --- /dev/null +++ b/node_modules/cycle/cycle.js @@ -0,0 +1,170 @@ +/* + 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 $ref, apply, call, decycle, hasOwnProperty, length, prototype, push, + retrocycle, stringify, test, toString +*/ + +var cycle = exports; + +cycle.decycle = function decycle(object) { + 'use strict'; + +// Make a deep copy of an object or array, assuring that there is at most +// one instance of each object or array in the resulting structure. The +// duplicate references (which might be forming cycles) are replaced with +// an object of the form +// {$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 + paths = []; // Keep the path to each unique object or array + + return (function derez(value, path) { + +// 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. + + if (typeof value === 'object' && value !== null && + !(value instanceof Boolean) && + !(value instanceof Date) && + !(value instanceof Number) && + !(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 + ']'); + } + } 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) + ']'); + } + } + } + return nu; + } + return value; + }(object, '$')); +}; + + +cycle.retrocycle = function retrocycle($) { + 'use strict'; + +// Restore an object that was reduced by decycle. Members whose values are +// objects of the form +// {$ref: PATH} +// are replaced with references to the value found by the PATH. This will +// restore cycles. The object will be mutated. + +// The eval function is used to locate the values described by a PATH. The +// root object is kept in a $ variable. A regular expression is used to +// assure that the PATH is extremely well formed. The regexp contains nested +// * quantifiers. That has been known to have extremely bad performance +// problems on some browsers for very long strings. A PATH is expected to be +// reasonably short. A PATH is allowed to belong to a very restricted subset of +// Goessner's JSONPath. + +// So, +// var s = '[{"$ref":"$"}]'; +// return JSON.retrocycle(JSON.parse(s)); +// produces an array containing a single element which is the array itself. + + var px = + /^\$(?:\[(?:\d+|\"(?:[^\\\"\u0000-\u001f]|\\([\\\"\/bfnrt]|u[0-9a-zA-Z]{4}))*\")\])*$/; + + (function rez(value) { + +// The rez function walks recursively through the object looking for $ref +// properties. When it finds one that has a value that is a path, then it +// replaces the $ref object with a reference to the value that is found by +// the path. + + var i, item, name, path; + + if (value && typeof value === 'object') { + if (Object.prototype.toString.apply(value) === '[object Array]') { + for (i = 0; i < value.length; i += 1) { + item = value[i]; + if (item && typeof item === 'object') { + path = item.$ref; + if (typeof path === 'string' && px.test(path)) { + value[i] = eval(path); + } else { + rez(item); + } + } + } + } else { + for (name in value) { + if (typeof value[name] === 'object') { + item = value[name]; + if (item) { + path = item.$ref; + if (typeof path === 'string' && px.test(path)) { + value[name] = eval(path); + } else { + rez(item); + } + } + } + } + } + } + }($)); + return $; +}; |