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object-utils

inheritance, mixins and other stuff, mainly to encapsulate objects

Dieses Skript sollte nicht direkt installiert werden. Es handelt sich hier um eine Bibliothek für andere Skripte, welche über folgenden Befehl in den Metadaten eines Skriptes eingebunden wird // @require https://update.greasyfork.org/scripts/22752/146271/object-utils.js

// ==UserScript==
// @name            object-utils
// @name:de         object-utils
// @namespace       dannysaurus.camamba
// @version         0.1
// @license         MIT License
// @description     inheritance, mixins and other stuff, mainly to encapsulate objects
// @description:de  inheritance, mixins and other stuff, mainly to encapsulate objects
// ==/UserScript==

var LIB = LIB || {};
/**
 *
 * @type {{mixin, extend, TruthyFalsy, Truthy, Falsy, Keeper, BackingData, emptyFunction, emptyDate}}
 */
LIB.objectUtils = (function() {
    'use strict';
    /**
     * Extends an object from another object through the prototype chain
     * @param {Object} superObj - The object to be extended
     * @param {Object} obj - The object extending the superObj
     * @return {boolean} true, if executed successfully
     */
    function _extend(superObj, obj){
        if (typeof superObj === 'undefined') return false;
        if (typeof obj === 'undefined') return false;
        // save properties of prototype of the obj
        var descriptors = {};
        Object.getOwnPropertyNames(obj.prototype).forEach(function(propName) {
            descriptors[propName] = Object.getOwnPropertyDescriptor(obj.prototype, propName);
        });
        // create a new extended prototype
        obj.prototype = Object.create(superObj.prototype, descriptors);
        obj.prototype.constructor = obj;
        return true;
    }
    /**
     * Clones properties from one object to another.
     * A property only gets cloned if it does not yet exist in the target object.
     * @param {Object} receiver - the target object receiver the properties
     * @param {Object} supplier - the source object supplying the properties
     * @param {Array} [props] - names of the relevant properties
     * @return {boolean} true, if executed successfully
     */
    function _mixin(receiver, supplier, props) {
        if (typeof supplier !== 'object' || typeof receiver !== 'object') {
            return false;
        }
        var propNames = Array.isArray(props) ? props : Object.getOwnPropertyNames(supplier);
        propNames.forEach(function(propName) {
            if (!Object.prototype.hasOwnProperty.call(receiver, propName)) {
                var desc = Object.getOwnPropertyDescriptor(supplier, propName);
                if (typeof desc !== 'undefined') {
                    Object.defineProperty(receiver, propName, desc);
                }
            }
        });
        return true;
    }

    /**
     * Has an object extending a super object by their prototype objects.
     * @param {Object} obj - The extending object
     * @return {{from: extendFrom, mixWith: mixWith}}
     */
    var extend = function(obj) {
        /**
         * Clones the prototype properties of the super object in the target object if the property does not yet exist there.
         * @param {Object} superObj - the source object supplying the properties
         * @param {Array} [props] - names of the relevant properties
         * @return {{thenWith: mixWith}}
         */
        var mixWith = function(superObj, props) {
            if (_mixin(obj.prototype, superObj.prototype, props)){
                return {
                    thenWith : mixWith
                };
            }
        };
        /**
         * Extends the super object from the prototype chain
         * @param superObj The super object to be extended
         * @return {{mixWith: mixWith}}
         */
        var extendFrom = function (superObj) {
            if (_extend(superObj, obj)) {
                return {
                    mixWith : mixWith
                };
            }
        };

        return {
            from : extendFrom,
            mixWith : mixWith
        };
    };

    /**
     * Defines an object that holds a value and specific values.
     * In case the value is a Truthy, Falsy or undefined it is overwritten with specific values.
     * @param value The common value.
     * @param [ifTruthy] if not undefined it overwrites value when it is a Truthy
     * @param [ifFalsy] if not undefined it overwrites value when it is a Falsy
     * @param [ifUndefined] if not undefined it overwrites value when it is undefined
     * @returns {TruthyFalsy}
     * @constructor
     */
    function TruthyFalsy(value, ifTruthy, ifFalsy, ifUndefined) {
        if (!this instanceof TruthyFalsy) {
            return new TruthyFalsy(value, ifTruthy, ifFalsy, ifUndefined);
        }
        this.value = value;
        if (ifTruthy !== 'undefined') { this.ifTruthy = ifTruthy; }
        if (ifFalsy !== 'undefined') { this.ifFalsy = ifFalsy; }
        if (ifUndefined !== 'undefined') { this.ifUndefined = ifUndefined; }
    }
    TruthyFalsy.prototype = {
        constructor : TruthyFalsy,
        valueOf: function() {
            var result = this.value;
            if (typeof this.ifUndefined !== "undefined" && typeof result === "undefined") {
                result = this.ifUndefined;
            } else if (typeof this.ifTruthy !== "undefined" && result) {
                result = this.ifTruthy;
            } else if (typeof this.ifFalsy !== "undefined" && result) {
                result = this.ifFalsy;
            }
            return result;
        },
        toString: function() {
            return String(this.valueOf());
        }
    };

    function Falsy(value, ifFalsy, ifUndefined) {
        if (!(this instanceof Falsy)) {
            return new Falsy(value, ifFalsy, ifUndefined);
        }
        TruthyFalsy.call(this, value, undefined, ifFalsy, ifUndefined);
    }
    extend(Falsy).from(TruthyFalsy);

    function Truthy(value, ifTruthy, ifUndefined) {
        if (!(this instanceof Truthy)) {
            return new Truthy(value, ifTruthy, ifUndefined);
        }
        TruthyFalsy.call(this, value, ifTruthy, undefined, ifUndefined);
    }
    extend(Truthy).from(TruthyFalsy);

    /**
     * Keeps elements assigned by an index
     * @param {number} [initialCapacity] - initial size of the array used to store the elements
     * @constructor
     */
    function Keeper(initialCapacity) {
        if (!(this instanceof Keeper)) {
            return new Keeper(initialCapacity);
        }
        var _store = new Array(initialCapacity || 16);
        var _pointer = 0;
        Object.defineProperties(this, {
            store: {
                get: function() { return _store },
                configurable: false, enumerable: false
            },
            pointer: {
                get: function() { return _pointer },
                configurable: false, enumerable: false
            }
        })
    }
    Keeper.prototype = {
        constructor: Keeper,
        /**
         * Adds a new element
         * @param {*|Object} item - The element to keep. Must not be type of <code>undefined</code>.
         * @return {number} The index (key) of the added element.<br>
         *                  <code>-1</code> if the element could not be added.
         */
        push: function(item) {
            if (typeof item !== 'undefined') {
                var index = this.pointer;
                this.store[index] = item;
                for (this.pointer = index + 1; this.pointer <= this.store.length; this.pointer++) {
                    if (typeof this.store[pointer] === 'undefined') { break; }
                }
                if (this.pointer === this.store.length) {
                    this.store.length *= 2;
                }
                return index;
            }
            return -1;
        },
        /**
         * Removes an element.
         * @param index The index (key) of the element to be removed.
         * @return {boolean} <code>true</code> if the element could be removed successfully
         */
        remove: function(index) {
            if (index + 1 >= this.store.length) {
                this.store[index] = undefined;
                this.pointer = index;
                return true;
            }
            return false;
        },
        /**
         * Gets the element with the specified index
         * @param {number} index - Index (key) of the element
         * @return {*|Object} the element with the specified index or <code>undefined</code>
         */
        get: function (index) {
            if (index + 1 <= this.store.length) {
                return this.store[index];
            }
            return undefined;
        }
    };

    /**
     * This callback is displayed as part of the Requester class.
     * @callback OnSetCallback
     * @param {*} oldValue - old value
     * @param {*} newValue - new value to be set
     */

    /**
     * Defines an accessor properties
     * @param {Object} sourceNode - the source object with the defining property
     * @param {Object} targetNode - the target object to define the accessor property
     * @param {string} propertyName - the name of the property which must exist on the <code>sourceNode</code>
     * @param {OnSetCallback} [onSetCallback] - called when the property gets assigned a value on the <code>targetNode</code>
     */
    var definePropRecursive = function(sourceNode, targetNode, propertyName, onSetCallback) {
        if (typeof onSetCallback !== "function") {
            onSetCallback = emptyFunction;
        }
        var srcProperty = sourceNode[propertyName];
        var isNode = (srcProperty !== null && typeof srcProperty === 'object' && Object.getPrototypeOf(srcProperty) === Object.prototype);
        if (isNode) {
            var childrenPropertyNames = Object.keys(srcProperty);
            var targetProperty = targetNode[propertyName] = {};
            childrenPropertyNames.forEach(function(childPropName) {
                definePropRecursive(srcProperty, targetProperty, childPropName, onSetCallback);
            });
        } else {
            Object.defineProperty(targetNode, propertyName, {
                enumerable: true,
                configurable: true,
                get: function() { return sourceNode[propertyName]; },
                set: function(value) {
                    onSetCallback(sourceNode[propertyName], value);
                    sourceNode[propertyName] = value;
                }
            });
        }
    };

    /**
     * Backing data that can be stored in the userscript database.
     * intially defines getter and setter on the front
     * @param {Object} frontObject - the object to define the properties on according to <code>dataObject</code>
     * @param {Object} dataObject - the Object defining the backing data structure and initial values
     * @param {string} dbKey - key for storing the data in the userscript db
     * @param {OnSetCallback} [onSet] - function called when a property of <code>dataObject</code> gets assigned a value through the <code>frontObject</code>
     * @returns {BackingData}
     * @constructor
     */
    function BackingData(frontObject, dataObject, dbKey, onSet) {
        if (!(this instanceof BackingData)) {
            return new BackingData(frontObject, dataObject, dbKey, onSet);
        }
        _mixin(this, dataObject);
        Object.defineProperties(this, {
            dbKey: { enumerable: false, configurable: true, writable: true, value: dbKey },
            frontObject: { enumerable: false, configurable: true, writable: true, value: frontObject },
            onSet: { enumerable: false, configurable: true, writable: true, value: onSet }
        });
        Object.keys(this).forEach(function(propName) {
            definePropRecursive(this, frontObject, propName, onSet);
        }, this);
    }
    BackingData.prototype = {
        constructor: BackingData,
        load: function() {
            var loadedObjSerialized = GM_getValue(this.dbKey);
            if (typeof loadedObjSerialized === "undefined") {
                return false;
            }

            var loadedObj = JSON.parse(loadedObjSerialized);
            Object.keys(this).forEach(function(propName) {
                var prop = loadedObj[propName];
                if (typeof prop !== "undefined") {
                    this[propName] = prop;
                }
            }, this);
            Object.keys(this).forEach(function(propName) {
                definePropRecursive(this, this.frontObject, propName, this.onSet);
            }, this);
            return true;
        },
        save: function() {
            var savingObj = {};
            _mixin(savingObj, this);
            var savingObjSerialized = JSON.stringify(savingObj);
            GM_setValue(this.dbKey, savingObjSerialized);
        },
        remove: function() {
            GM_deleteValue(this.dbKey);
        }
    };

    /** placeholder for empty callbacks */
    function emptyFunction() {}
    /** placeholder for an undefined date */
    var emptyDate = new Date('invalid');

    return {
        mixin: _mixin,
        extend: extend,
        TruthyFalsy: TruthyFalsy,
        Truthy: Truthy,
        Falsy: Falsy,
        Keeper: Keeper,
        BackingData: BackingData,
        get emptyFunction() { return emptyFunction },
        get emptyDate() { return emptyDate }
    };
})();