Object.defineProperty polyfill

defineProperty.js

/*!
 * https://github.com/es-shims/es5-shim
 * @license es5-shim Copyright 2009-2015 by contributors, MIT License
 * see https://github.com/es-shims/es5-shim/blob/master/LICENSE
 */

// vim: ts=4 sts=4 sw=4 expandtab

// Add semicolon to prevent IIFE from being passed as argument to concatenated code.
;

// UMD (Universal Module Definition)
// see https://github.com/umdjs/umd/blob/master/templates/returnExports.js
(function (root, factory) {
    'use strict';

    /* global define, exports, module */
    if (typeof define === 'function' && define.amd) {
        // AMD. Register as an anonymous module.
        define(factory);
    } else if (typeof exports === 'object') {
        // Node. Does not work with strict CommonJS, but
        // only CommonJS-like enviroments that support module.exports,
        // like Node.
        module.exports = factory();
    } else {
        // Browser globals (root is window)
        root.returnExports = factory();
    }
}(this, function () {

    var call = Function.call;
    var prototypeOfObject = Object.prototype;
    var owns = call.bind(prototypeOfObject.hasOwnProperty);
    var isEnumerable = call.bind(prototypeOfObject.propertyIsEnumerable);
    var toStr = call.bind(prototypeOfObject.toString);

    // If JS engine supports accessors creating shortcuts.
    var defineGetter;
    var defineSetter;
    var lookupGetter;
    var lookupSetter;
    var supportsAccessors = owns(prototypeOfObject, '__defineGetter__');
    if (supportsAccessors) {
        /* eslint-disable no-underscore-dangle, no-restricted-properties */
        defineGetter = call.bind(prototypeOfObject.__defineGetter__);
        defineSetter = call.bind(prototypeOfObject.__defineSetter__);
        lookupGetter = call.bind(prototypeOfObject.__lookupGetter__);
        lookupSetter = call.bind(prototypeOfObject.__lookupSetter__);
        /* eslint-enable no-underscore-dangle, no-restricted-properties */
    }

    var isPrimitive = function isPrimitive(o) {
        return o == null || (typeof o !== 'object' && typeof o !== 'function');
    };

    // ES5 15.2.3.2
    // http://es5.github.com/#x15.2.3.2
    if (!Object.getPrototypeOf) {
        // https://github.com/es-shims/es5-shim/issues#issue/2
        // http://ejohn.org/blog/objectgetprototypeof/
        // recommended by fschaefer on github
        //
        // sure, and webreflection says ^_^
        // ... this will nerever possibly return null
        // ... Opera Mini breaks here with infinite loops
        Object.getPrototypeOf = function getPrototypeOf(object) {
            // eslint-disable-next-line no-proto
            var proto = object.__proto__;
            if (proto || proto === null) {
                return proto;
            } else if (toStr(object.constructor) === '[object Function]') {
                return object.constructor.prototype;
            } else if (object instanceof Object) {
                return prototypeOfObject;
            } else {
                // Correctly return null for Objects created with `Object.create(null)`
                // (shammed or native) or `{ __proto__: null}`.  Also returns null for
                // cross-realm objects on browsers that lack `__proto__` support (like
                // IE <11), but that's the best we can do.
                return null;
            }
        };
    }

    // ES5 15.2.3.3
    // http://es5.github.com/#x15.2.3.3

    var doesGetOwnPropertyDescriptorWork = function doesGetOwnPropertyDescriptorWork(object) {
        try {
            object.sentinel = 0;
            return Object.getOwnPropertyDescriptor(object, 'sentinel').value === 0;
        } catch (exception) {
            return false;
        }
    };

    // check whether getOwnPropertyDescriptor works if it's given. Otherwise, shim partially.
    if (Object.defineProperty) {
        var getOwnPropertyDescriptorWorksOnObject = doesGetOwnPropertyDescriptorWork({});
        var getOwnPropertyDescriptorWorksOnDom = typeof document === 'undefined' ||
        doesGetOwnPropertyDescriptorWork(document.createElement('div'));
        if (!getOwnPropertyDescriptorWorksOnDom || !getOwnPropertyDescriptorWorksOnObject) {
            var getOwnPropertyDescriptorFallback = Object.getOwnPropertyDescriptor;
        }
    }

    if (!Object.getOwnPropertyDescriptor || getOwnPropertyDescriptorFallback) {
        var ERR_NON_OBJECT = 'Object.getOwnPropertyDescriptor called on a non-object: ';

        /* eslint-disable no-proto */
        Object.getOwnPropertyDescriptor = function getOwnPropertyDescriptor(object, property) {
            if (isPrimitive(object)) {
                throw new TypeError(ERR_NON_OBJECT + object);
            }

            // make a valiant attempt to use the real getOwnPropertyDescriptor
            // for I8's DOM elements.
            if (getOwnPropertyDescriptorFallback) {
                try {
                    return getOwnPropertyDescriptorFallback.call(Object, object, property);
                } catch (exception) {
                    // try the shim if the real one doesn't work
                }
            }

            var descriptor;

            // If object does not owns property return undefined immediately.
            if (!owns(object, property)) {
                return descriptor;
            }

            // If object has a property then it's for sure `configurable`, and
            // probably `enumerable`. Detect enumerability though.
            descriptor = {
                enumerable: isEnumerable(object, property),
                configurable: true
            };

            // If JS engine supports accessor properties then property may be a
            // getter or setter.
            if (supportsAccessors) {
                // Unfortunately `__lookupGetter__` will return a getter even
                // if object has own non getter property along with a same named
                // inherited getter. To avoid misbehavior we temporary remove
                // `__proto__` so that `__lookupGetter__` will return getter only
                // if it's owned by an object.
                var prototype = object.__proto__;
                var notPrototypeOfObject = object !== prototypeOfObject;
                // avoid recursion problem, breaking in Opera Mini when
                // Object.getOwnPropertyDescriptor(Object.prototype, 'toString')
                // or any other Object.prototype accessor
                if (notPrototypeOfObject) {
                    object.__proto__ = prototypeOfObject;
                }

                var getter = lookupGetter(object, property);
                var setter = lookupSetter(object, property);

                if (notPrototypeOfObject) {
                    // Once we have getter and setter we can put values back.
                    object.__proto__ = prototype;
                }

                if (getter || setter) {
                    if (getter) {
                        descriptor.get = getter;
                    }
                    if (setter) {
                        descriptor.set = setter;
                    }
                    // If it was accessor property we're done and return here
                    // in order to avoid adding `value` to the descriptor.
                    return descriptor;
                }
            }

            // If we got this far we know that object has an own property that is
            // not an accessor so we set it as a value and return descriptor.
            descriptor.value = object[property];
            descriptor.writable = true;
            return descriptor;
        };
        /* eslint-enable no-proto */
    }

    // ES5 15.2.3.4
    // http://es5.github.com/#x15.2.3.4
    if (!Object.getOwnPropertyNames) {
        Object.getOwnPropertyNames = function getOwnPropertyNames(object) {
            return Object.keys(object);
        };
    }

    // ES5 15.2.3.5
    // http://es5.github.com/#x15.2.3.5
    if (!Object.create) {

        // Contributed by Brandon Benvie, October, 2012
        var createEmpty;
        var supportsProto = !({ __proto__: null } instanceof Object);
                            // the following produces false positives
                            // in Opera Mini => not a reliable check
                            // Object.prototype.__proto__ === null

        // Check for document.domain and active x support
        // No need to use active x approach when document.domain is not set
        // see https://github.com/es-shims/es5-shim/issues/150
        // variation of https://github.com/kitcambridge/es5-shim/commit/4f738ac066346
        /* global ActiveXObject */
        var shouldUseActiveX = function shouldUseActiveX() {
            // return early if document.domain not set
            if (!document.domain) {
                return false;
            }

            try {
                return !!new ActiveXObject('htmlfile');
            } catch (exception) {
                return false;
            }
        };

        // This supports IE8 when document.domain is used
        // see https://github.com/es-shims/es5-shim/issues/150
        // variation of https://github.com/kitcambridge/es5-shim/commit/4f738ac066346
        var getEmptyViaActiveX = function getEmptyViaActiveX() {
            var empty;
            var xDoc;

            xDoc = new ActiveXObject('htmlfile');

            var script = 'script';
            xDoc.write('<' + script + '></' + script + '>');
            xDoc.close();

            empty = xDoc.parentWindow.Object.prototype;
            xDoc = null;

            return empty;
        };

        // The original implementation using an iframe
        // before the activex approach was added
        // see https://github.com/es-shims/es5-shim/issues/150
        var getEmptyViaIFrame = function getEmptyViaIFrame() {
            var iframe = document.createElement('iframe');
            var parent = document.body || document.documentElement;
            var empty;

            iframe.style.display = 'none';
            parent.appendChild(iframe);
            // eslint-disable-next-line no-script-url
            iframe.src = 'javascript:';

            empty = iframe.contentWindow.Object.prototype;
            parent.removeChild(iframe);
            iframe = null;

            return empty;
        };

        /* global document */
        if (supportsProto || typeof document === 'undefined') {
            createEmpty = function () {
                return { __proto__: null };
            };
        } else {
            // In old IE __proto__ can't be used to manually set `null`, nor does
            // any other method exist to make an object that inherits from nothing,
            // aside from Object.prototype itself. Instead, create a new global
            // object and *steal* its Object.prototype and strip it bare. This is
            // used as the prototype to create nullary objects.
            createEmpty = function () {
                // Determine which approach to use
                // see https://github.com/es-shims/es5-shim/issues/150
                var empty = shouldUseActiveX() ? getEmptyViaActiveX() : getEmptyViaIFrame();

                delete empty.constructor;
                delete empty.hasOwnProperty;
                delete empty.propertyIsEnumerable;
                delete empty.isPrototypeOf;
                delete empty.toLocaleString;
                delete empty.toString;
                delete empty.valueOf;

                var Empty = function Empty() {};
                Empty.prototype = empty;
                // short-circuit future calls
                createEmpty = function () {
                    return new Empty();
                };
                return new Empty();
            };
        }

        Object.create = function create(prototype, properties) {

            var object;
            var Type = function Type() {}; // An empty constructor.

            if (prototype === null) {
                object = createEmpty();
            } else {
                if (prototype !== null && isPrimitive(prototype)) {
                    // In the native implementation `parent` can be `null`
                    // OR *any* `instanceof Object`  (Object|Function|Array|RegExp|etc)
                    // Use `typeof` tho, b/c in old IE, DOM elements are not `instanceof Object`
                    // like they are in modern browsers. Using `Object.create` on DOM elements
                    // is...err...probably inappropriate, but the native version allows for it.
                    throw new TypeError('Object prototype may only be an Object or null'); // same msg as Chrome
                }
                Type.prototype = prototype;
                object = new Type();
                // IE has no built-in implementation of `Object.getPrototypeOf`
                // neither `__proto__`, but this manually setting `__proto__` will
                // guarantee that `Object.getPrototypeOf` will work as expected with
                // objects created using `Object.create`
                // eslint-disable-next-line no-proto
                object.__proto__ = prototype;
            }

            if (properties !== void 0) {
                Object.defineProperties(object, properties);
            }

            return object;
        };
    }

    // ES5 15.2.3.6
    // http://es5.github.com/#x15.2.3.6

    // Patch for WebKit and IE8 standard mode
    // Designed by hax <hax.github.com>
    // related issue: https://github.com/es-shims/es5-shim/issues#issue/5
    // IE8 Reference:
    //     http://msdn.microsoft.com/en-us/library/dd282900.aspx
    //     http://msdn.microsoft.com/en-us/library/dd229916.aspx
    // WebKit Bugs:
    //     https://bugs.webkit.org/show_bug.cgi?id=36423

    var doesDefinePropertyWork = function doesDefinePropertyWork(object) {
        try {
            Object.defineProperty(object, 'sentinel', {});
            return 'sentinel' in object;
        } catch (exception) {
            return false;
        }
    };

    // check whether defineProperty works if it's given. Otherwise,
    // shim partially.
    if (Object.defineProperty) {
        var definePropertyWorksOnObject = doesDefinePropertyWork({});
        var definePropertyWorksOnDom = typeof document === 'undefined' ||
            doesDefinePropertyWork(document.createElement('div'));
        if (!definePropertyWorksOnObject || !definePropertyWorksOnDom) {
            var definePropertyFallback = Object.defineProperty,
                definePropertiesFallback = Object.defineProperties;
        }
    }

    if (!Object.defineProperty || definePropertyFallback) {
        var ERR_NON_OBJECT_DESCRIPTOR = 'Property description must be an object: ';
        var ERR_NON_OBJECT_TARGET = 'Object.defineProperty called on non-object: ';
        var ERR_ACCESSORS_NOT_SUPPORTED = 'getters & setters can not be defined on this javascript engine';

        Object.defineProperty = function defineProperty(object, property, descriptor) {
            if (isPrimitive(object)) {
                throw new TypeError(ERR_NON_OBJECT_TARGET + object);
            }
            if (isPrimitive(descriptor)) {
                throw new TypeError(ERR_NON_OBJECT_DESCRIPTOR + descriptor);
            }
            // make a valiant attempt to use the real defineProperty
            // for I8's DOM elements.
            if (definePropertyFallback) {
                try {
                    return definePropertyFallback.call(Object, object, property, descriptor);
                } catch (exception) {
                    // try the shim if the real one doesn't work
                }
            }

            // If it's a data property.
            if ('value' in descriptor) {
                // fail silently if 'writable', 'enumerable', or 'configurable'
                // are requested but not supported
                /*
                // alternate approach:
                if ( // can't implement these features; allow false but not true
                    ('writable' in descriptor && !descriptor.writable) ||
                    ('enumerable' in descriptor && !descriptor.enumerable) ||
                    ('configurable' in descriptor && !descriptor.configurable)
                ))
                    throw new RangeError(
                        'This implementation of Object.defineProperty does not support configurable, enumerable, or writable.'
                    );
                */

                if (supportsAccessors && (lookupGetter(object, property) || lookupSetter(object, property))) {
                    // As accessors are supported only on engines implementing
                    // `__proto__` we can safely override `__proto__` while defining
                    // a property to make sure that we don't hit an inherited
                    // accessor.
                    /* eslint-disable no-proto */
                    var prototype = object.__proto__;
                    object.__proto__ = prototypeOfObject;
                    // Deleting a property anyway since getter / setter may be
                    // defined on object itself.
                    delete object[property];
                    object[property] = descriptor.value;
                    // Setting original `__proto__` back now.
                    object.__proto__ = prototype;
                    /* eslint-enable no-proto */
                } else {
                    object[property] = descriptor.value;
                }
            } else {
                var hasGetter = 'get' in descriptor;
                var hasSetter = 'set' in descriptor;
                if (!supportsAccessors && (hasGetter || hasSetter)) {
                    throw new TypeError(ERR_ACCESSORS_NOT_SUPPORTED);
                }
                // If we got that far then getters and setters can be defined !!
                if (hasGetter) {
                    defineGetter(object, property, descriptor.get);
                }
                if (hasSetter) {
                    defineSetter(object, property, descriptor.set);
                }
            }
            return object;
        };
    }

    // ES5 15.2.3.7
    // http://es5.github.com/#x15.2.3.7
    if (!Object.defineProperties || definePropertiesFallback) {
        Object.defineProperties = function defineProperties(object, properties) {
            // make a valiant attempt to use the real defineProperties
            if (definePropertiesFallback) {
                try {
                    return definePropertiesFallback.call(Object, object, properties);
                } catch (exception) {
                    // try the shim if the real one doesn't work
                }
            }

            Object.keys(properties).forEach(function (property) {
                if (property !== '__proto__') {
                    Object.defineProperty(object, property, properties[property]);
                }
            });
            return object;
        };
    }

    // ES5 15.2.3.8
    // http://es5.github.com/#x15.2.3.8
    if (!Object.seal) {
        Object.seal = function seal(object) {
            if (Object(object) !== object) {
                throw new TypeError('Object.seal can only be called on Objects.');
            }
            // this is misleading and breaks feature-detection, but
            // allows "securable" code to "gracefully" degrade to working
            // but insecure code.
            return object;
        };
    }

    // ES5 15.2.3.9
    // http://es5.github.com/#x15.2.3.9
    if (!Object.freeze) {
        Object.freeze = function freeze(object) {
            if (Object(object) !== object) {
                throw new TypeError('Object.freeze can only be called on Objects.');
            }
            // this is misleading and breaks feature-detection, but
            // allows "securable" code to "gracefully" degrade to working
            // but insecure code.
            return object;
        };
    }

    // detect a Rhino bug and patch it
    try {
        Object.freeze(function () {});
    } catch (exception) {
        Object.freeze = (function (freezeObject) {
            return function freeze(object) {
                if (typeof object === 'function') {
                    return object;
                } else {
                    return freezeObject(object);
                }
            };
        }(Object.freeze));
    }

    // ES5 15.2.3.10
    // http://es5.github.com/#x15.2.3.10
    if (!Object.preventExtensions) {
        Object.preventExtensions = function preventExtensions(object) {
            if (Object(object) !== object) {
                throw new TypeError('Object.preventExtensions can only be called on Objects.');
            }
            // this is misleading and breaks feature-detection, but
            // allows "securable" code to "gracefully" degrade to working
            // but insecure code.
            return object;
        };
    }

    // ES5 15.2.3.11
    // http://es5.github.com/#x15.2.3.11
    if (!Object.isSealed) {
        Object.isSealed = function isSealed(object) {
            if (Object(object) !== object) {
                throw new TypeError('Object.isSealed can only be called on Objects.');
            }
            return false;
        };
    }

    // ES5 15.2.3.12
    // http://es5.github.com/#x15.2.3.12
    if (!Object.isFrozen) {
        Object.isFrozen = function isFrozen(object) {
            if (Object(object) !== object) {
                throw new TypeError('Object.isFrozen can only be called on Objects.');
            }
            return false;
        };
    }

    // ES5 15.2.3.13
    // http://es5.github.com/#x15.2.3.13
    if (!Object.isExtensible) {
        Object.isExtensible = function isExtensible(object) {
            // 1. If Type(O) is not Object throw a TypeError exception.
            if (Object(object) !== object) {
                throw new TypeError('Object.isExtensible can only be called on Objects.');
            }
            // 2. Return the Boolean value of the [[Extensible]] internal property of O.
            var name = '';
            while (owns(object, name)) {
                name += '?';
            }
            object[name] = true;
            var returnValue = owns(object, name);
            delete object[name];
            return returnValue;
        };
    }

}));