ZeroMe/js/lib/maquette.js

(function (root, factory) {
    if (typeof define === 'function' && define.amd) {
        // AMD. Register as an anonymous module.
        define(['exports'], factory);
    } else if (typeof exports === 'object' && typeof exports.nodeName !== 'string') {
        // CommonJS
        factory(exports);
    } else {
        // Browser globals
        factory(root.maquette = {});
    }
}(this, function (exports) {
    'use strict';
    ;
    ;
    ;
    ;
    var NAMESPACE_W3 = 'http://www.w3.org/';
    var NAMESPACE_SVG = NAMESPACE_W3 + '2000/svg';
    var NAMESPACE_XLINK = NAMESPACE_W3 + '1999/xlink';
    // Utilities
    var emptyArray = [];
    var extend = function (base, overrides) {
        var result = {};
        Object.keys(base).forEach(function (key) {
            result[key] = base[key];
        });
        if (overrides) {
            Object.keys(overrides).forEach(function (key) {
                result[key] = overrides[key];
            });
        }
        return result;
    };
    // Hyperscript helper functions
    var same = function (vnode1, vnode2) {
        if (vnode1.vnodeSelector !== vnode2.vnodeSelector) {
            return false;
        }
        if (vnode1.properties && vnode2.properties) {
            if (vnode1.properties.key !== vnode2.properties.key) {
                return false;
            }
            return vnode1.properties.bind === vnode2.properties.bind;
        }
        return !vnode1.properties && !vnode2.properties;
    };
    var toTextVNode = function (data) {
        return {
            vnodeSelector: '',
            properties: undefined,
            children: undefined,
            text: data.toString(),
            domNode: null
        };
    };
    var appendChildren = function (parentSelector, insertions, main) {
        for (var i = 0; i < insertions.length; i++) {
            var item = insertions[i];
            if (Array.isArray(item)) {
                appendChildren(parentSelector, item, main);
            } else {
                if (item !== null && item !== undefined) {
                    if (!item.hasOwnProperty('vnodeSelector')) {
                        item = toTextVNode(item);
                    }
                    main.push(item);
                }
            }
        }
    };
    // Render helper functions
    var missingTransition = function () {
        throw new Error('Provide a transitions object to the projectionOptions to do animations');
    };
    var DEFAULT_PROJECTION_OPTIONS = {
        namespace: undefined,
        eventHandlerInterceptor: undefined,
        styleApplyer: function (domNode, styleName, value) {
            // Provides a hook to add vendor prefixes for browsers that still need it.
            domNode.style[styleName] = value;
        },
        transitions: {
            enter: missingTransition,
            exit: missingTransition
        }
    };
    var applyDefaultProjectionOptions = function (projectorOptions) {
        return extend(DEFAULT_PROJECTION_OPTIONS, projectorOptions);
    };
    var checkStyleValue = function (styleValue) {
        if (typeof styleValue !== 'string') {
            throw new Error('Style values must be strings');
        }
    };
    var setProperties = function (domNode, properties, projectionOptions) {
        if (!properties) {
            return;
        }
        var eventHandlerInterceptor = projectionOptions.eventHandlerInterceptor;
        var propNames = Object.keys(properties);
        var propCount = propNames.length;
        for (var i = 0; i < propCount; i++) {
            var propName = propNames[i];
            /* tslint:disable:no-var-keyword: edge case */
            var propValue = properties[propName];
            /* tslint:enable:no-var-keyword */
            if (propName === 'className') {
                throw new Error('Property "className" is not supported, use "class".');
            } else if (propName === 'class') {
                if (domNode.className) {
                    // May happen if classes is specified before class
                    domNode.className += ' ' + propValue;
                } else {
                    domNode.className = propValue;
                }
            } else if (propName === 'classes') {
                // object with string keys and boolean values
                var classNames = Object.keys(propValue);
                var classNameCount = classNames.length;
                for (var j = 0; j < classNameCount; j++) {
                    var className = classNames[j];
                    if (propValue[className]) {
                        domNode.classList.add(className);
                    }
                }
            } else if (propName === 'styles') {
                // object with string keys and string (!) values
                var styleNames = Object.keys(propValue);
                var styleCount = styleNames.length;
                for (var j = 0; j < styleCount; j++) {
                    var styleName = styleNames[j];
                    var styleValue = propValue[styleName];
                    if (styleValue) {
                        checkStyleValue(styleValue);
                        projectionOptions.styleApplyer(domNode, styleName, styleValue);
                    }
                }
            } else if (propName === 'key') {
                continue;
            } else if (propValue === null || propValue === undefined) {
                continue;
            } else {
                var type = typeof propValue;
                if (type === 'function') {
                    if (propName.lastIndexOf('on', 0) === 0) {
                        if (eventHandlerInterceptor) {
                            propValue = eventHandlerInterceptor(propName, propValue, domNode, properties);    // intercept eventhandlers
                        }
                        if (propName === 'oninput') {
                            (function () {
                                // record the evt.target.value, because IE and Edge sometimes do a requestAnimationFrame between changing value and running oninput
                                var oldPropValue = propValue;
                                propValue = function (evt) {
                                    evt.target['oninput-value'] = evt.target.value;
                                    // may be HTMLTextAreaElement as well
                                    oldPropValue.apply(this, [evt]);
                                };
                            }());
                        }
                        domNode[propName] = propValue;
                    }
                } else if (type === 'string' && propName !== 'value' && propName !== 'innerHTML') {
                    if (projectionOptions.namespace === NAMESPACE_SVG && propName === 'href') {
                        domNode.setAttributeNS(NAMESPACE_XLINK, propName, propValue);
                    } else {
                        domNode.setAttribute(propName, propValue);
                    }
                } else {
                    domNode[propName] = propValue;
                }
            }
        }
    };
    var updateProperties = function (domNode, previousProperties, properties, projectionOptions) {
        if (!properties) {
            return;
        }
        var propertiesUpdated = false;
        var propNames = Object.keys(properties);
        var propCount = propNames.length;
        for (var i = 0; i < propCount; i++) {
            var propName = propNames[i];
            // assuming that properties will be nullified instead of missing is by design
            var propValue = properties[propName];
            var previousValue = previousProperties[propName];
            if (propName === 'class') {
                if (previousValue !== propValue) {
                    throw new Error('"class" property may not be updated. Use the "classes" property for conditional css classes.');
                }
            } else if (propName === 'classes') {
                var classList = domNode.classList;
                var classNames = Object.keys(propValue);
                var classNameCount = classNames.length;
                for (var j = 0; j < classNameCount; j++) {
                    var className = classNames[j];
                    var on = !!propValue[className];
                    var previousOn = !!previousValue[className];
                    if (on === previousOn) {
                        continue;
                    }
                    propertiesUpdated = true;
                    if (on) {
                        classList.add(className);
                    } else {
                        classList.remove(className);
                    }
                }
            } else if (propName === 'styles') {
                var styleNames = Object.keys(propValue);
                var styleCount = styleNames.length;
                for (var j = 0; j < styleCount; j++) {
                    var styleName = styleNames[j];
                    var newStyleValue = propValue[styleName];
                    var oldStyleValue = previousValue[styleName];
                    if (newStyleValue === oldStyleValue) {
                        continue;
                    }
                    propertiesUpdated = true;
                    if (newStyleValue) {
                        checkStyleValue(newStyleValue);
                        projectionOptions.styleApplyer(domNode, styleName, newStyleValue);
                    } else {
                        projectionOptions.styleApplyer(domNode, styleName, '');
                    }
                }
            } else {
                if (!propValue && typeof previousValue === 'string') {
                    propValue = '';
                }
                if (propName === 'value') {
                    if (domNode[propName] !== propValue && domNode['oninput-value'] !== propValue) {
                        domNode[propName] = propValue;
                        // Reset the value, even if the virtual DOM did not change
                        domNode['oninput-value'] = undefined;
                    }
                    // else do not update the domNode, otherwise the cursor position would be changed
                    if (propValue !== previousValue) {
                        propertiesUpdated = true;
                    }
                } else if (propValue !== previousValue) {
                    var type = typeof propValue;
                    if (type === 'function') {
                        throw new Error('Functions may not be updated on subsequent renders (property: ' + propName + '). Hint: declare event handler functions outside the render() function.');
                    }
                    if (type === 'string' && propName !== 'innerHTML') {
                        if (projectionOptions.namespace === NAMESPACE_SVG && propName === 'href') {
                            domNode.setAttributeNS(NAMESPACE_XLINK, propName, propValue);
                        } else {
                            domNode.setAttribute(propName, propValue);
                        }
                    } else {
                        if (domNode[propName] !== propValue) {
                            domNode[propName] = propValue;
                        }
                    }
                    propertiesUpdated = true;
                }
            }
        }
        return propertiesUpdated;
    };
    var findIndexOfChild = function (children, sameAs, start) {
        if (sameAs.vnodeSelector !== '') {
            // Never scan for text-nodes
            for (var i = start; i < children.length; i++) {
                if (same(children[i], sameAs)) {
                    return i;
                }
            }
        }
        return -1;
    };
    var nodeAdded = function (vNode, transitions) {
        if (vNode.properties) {
            var enterAnimation = vNode.properties.enterAnimation;
            if (enterAnimation) {
                if (typeof enterAnimation === 'function') {
                    enterAnimation(vNode.domNode, vNode.properties);
                } else {
                    transitions.enter(vNode.domNode, vNode.properties, enterAnimation);
                }
            }
        }
    };
    var nodeToRemove = function (vNode, transitions) {
        var domNode = vNode.domNode;
        if (vNode.properties) {
            var exitAnimation = vNode.properties.exitAnimation;
            if (exitAnimation) {
                domNode.style.pointerEvents = 'none';
                var removeDomNode = function () {
                    if (domNode.parentNode) {
                        domNode.parentNode.removeChild(domNode);
                    }
                };
                if (typeof exitAnimation === 'function') {
                    exitAnimation(domNode, removeDomNode, vNode.properties);
                    return;
                } else {
                    transitions.exit(vNode.domNode, vNode.properties, exitAnimation, removeDomNode);
                    return;
                }
            }
        }
        if (domNode.parentNode) {
            domNode.parentNode.removeChild(domNode);
        }
    };
    var checkDistinguishable = function (childNodes, indexToCheck, parentVNode, operation) {
        var childNode = childNodes[indexToCheck];
        if (childNode.vnodeSelector === '') {
            return;    // Text nodes need not be distinguishable
        }
        var properties = childNode.properties;
        var key = properties ? properties.key === undefined ? properties.bind : properties.key : undefined;
        if (!key) {
            for (var i = 0; i < childNodes.length; i++) {
                if (i !== indexToCheck) {
                    var node = childNodes[i];
                    if (same(node, childNode)) {
                        if (operation === 'added') {
                            throw new Error(parentVNode.vnodeSelector + ' had a ' + childNode.vnodeSelector + ' child ' + 'added, but there is now more than one. You must add unique key properties to make them distinguishable.');
                        } else {
                            throw new Error(parentVNode.vnodeSelector + ' had a ' + childNode.vnodeSelector + ' child ' + 'removed, but there were more than one. You must add unique key properties to make them distinguishable.');
                        }
                    }
                }
            }
        }
    };
    var createDom;
    var updateDom;
    var updateChildren = function (vnode, domNode, oldChildren, newChildren, projectionOptions) {
        if (oldChildren === newChildren) {
            return false;
        }
        oldChildren = oldChildren || emptyArray;
        newChildren = newChildren || emptyArray;
        var oldChildrenLength = oldChildren.length;
        var newChildrenLength = newChildren.length;
        var transitions = projectionOptions.transitions;
        var oldIndex = 0;
        var newIndex = 0;
        var i;
        var textUpdated = false;
        while (newIndex < newChildrenLength) {
            var oldChild = oldIndex < oldChildrenLength ? oldChildren[oldIndex] : undefined;
            var newChild = newChildren[newIndex];
            if (oldChild !== undefined && same(oldChild, newChild)) {
                textUpdated = updateDom(oldChild, newChild, projectionOptions) || textUpdated;
                oldIndex++;
            } else {
                var findOldIndex = findIndexOfChild(oldChildren, newChild, oldIndex + 1);
                if (findOldIndex >= 0) {
                    // Remove preceding missing children
                    for (i = oldIndex; i < findOldIndex; i++) {
                        nodeToRemove(oldChildren[i], transitions);
                        checkDistinguishable(oldChildren, i, vnode, 'removed');
                    }
                    textUpdated = updateDom(oldChildren[findOldIndex], newChild, projectionOptions) || textUpdated;
                    oldIndex = findOldIndex + 1;
                } else {
                    // New child
                    createDom(newChild, domNode, oldIndex < oldChildrenLength ? oldChildren[oldIndex].domNode : undefined, projectionOptions);
                    nodeAdded(newChild, transitions);
                    checkDistinguishable(newChildren, newIndex, vnode, 'added');
                }
            }
            newIndex++;
        }
        if (oldChildrenLength > oldIndex) {
            // Remove child fragments
            for (i = oldIndex; i < oldChildrenLength; i++) {
                nodeToRemove(oldChildren[i], transitions);
                checkDistinguishable(oldChildren, i, vnode, 'removed');
            }
        }
        return textUpdated;
    };
    var addChildren = function (domNode, children, projectionOptions) {
        if (!children) {
            return;
        }
        for (var i = 0; i < children.length; i++) {
            createDom(children[i], domNode, undefined, projectionOptions);
        }
    };
    var initPropertiesAndChildren = function (domNode, vnode, projectionOptions) {
        addChildren(domNode, vnode.children, projectionOptions);
        // children before properties, needed for value property of <select>.
        if (vnode.text) {
            domNode.textContent = vnode.text;
        }
        setProperties(domNode, vnode.properties, projectionOptions);
        if (vnode.properties && vnode.properties.afterCreate) {
            vnode.properties.afterCreate(domNode, projectionOptions, vnode.vnodeSelector, vnode.properties, vnode.children);
        }
    };
    createDom = function (vnode, parentNode, insertBefore, projectionOptions) {
        var domNode, i, c, start = 0, type, found;
        var vnodeSelector = vnode.vnodeSelector;
        if (vnodeSelector === '') {
            domNode = vnode.domNode = document.createTextNode(vnode.text);
            if (insertBefore !== undefined) {
                parentNode.insertBefore(domNode, insertBefore);
            } else {
                parentNode.appendChild(domNode);
            }
        } else {
            for (i = 0; i <= vnodeSelector.length; ++i) {
                c = vnodeSelector.charAt(i);
                if (i === vnodeSelector.length || c === '.' || c === '#') {
                    type = vnodeSelector.charAt(start - 1);
                    found = vnodeSelector.slice(start, i);
                    if (type === '.') {
                        domNode.classList.add(found);
                    } else if (type === '#') {
                        domNode.id = found;
                    } else {
                        if (found === 'svg') {
                            projectionOptions = extend(projectionOptions, { namespace: NAMESPACE_SVG });
                        }
                        if (projectionOptions.namespace !== undefined) {
                            domNode = vnode.domNode = document.createElementNS(projectionOptions.namespace, found);
                        } else {
                            domNode = vnode.domNode = document.createElement(found);
                        }
                        if (insertBefore !== undefined) {
                            parentNode.insertBefore(domNode, insertBefore);
                        } else {
                            parentNode.appendChild(domNode);
                        }
                    }
                    start = i + 1;
                }
            }
            initPropertiesAndChildren(domNode, vnode, projectionOptions);
        }
    };
    updateDom = function (previous, vnode, projectionOptions) {
        var domNode = previous.domNode;
        var textUpdated = false;
        if (previous === vnode) {
            return false;    // By contract, VNode objects may not be modified anymore after passing them to maquette
        }
        var updated = false;
        if (vnode.vnodeSelector === '') {
            if (vnode.text !== previous.text) {
                var newVNode = document.createTextNode(vnode.text);
                domNode.parentNode.replaceChild(newVNode, domNode);
                vnode.domNode = newVNode;
                textUpdated = true;
                return textUpdated;
            }
        } else {
            if (vnode.vnodeSelector.lastIndexOf('svg', 0) === 0) {
                projectionOptions = extend(projectionOptions, { namespace: NAMESPACE_SVG });
            }
            if (previous.text !== vnode.text) {
                updated = true;
                if (vnode.text === undefined) {
                    domNode.removeChild(domNode.firstChild);    // the only textnode presumably
                } else {
                    domNode.textContent = vnode.text;
                }
            }
            updated = updateChildren(vnode, domNode, previous.children, vnode.children, projectionOptions) || updated;
            updated = updateProperties(domNode, previous.properties, vnode.properties, projectionOptions) || updated;
            if (vnode.properties && vnode.properties.afterUpdate) {
                vnode.properties.afterUpdate(domNode, projectionOptions, vnode.vnodeSelector, vnode.properties, vnode.children);
            }
        }
        if (updated && vnode.properties && vnode.properties.updateAnimation) {
            vnode.properties.updateAnimation(domNode, vnode.properties, previous.properties);
        }
        vnode.domNode = previous.domNode;
        return textUpdated;
    };
    var createProjection = function (vnode, projectionOptions) {
        return {
            update: function (updatedVnode) {
                if (vnode.vnodeSelector !== updatedVnode.vnodeSelector) {
                    throw new Error('The selector for the root VNode may not be changed. (consider using dom.merge and add one extra level to the virtual DOM)');
                }
                updateDom(vnode, updatedVnode, projectionOptions);
                vnode = updatedVnode;
            },
            domNode: vnode.domNode
        };
    };
    ;
    // The other two parameters are not added here, because the Typescript compiler creates surrogate code for desctructuring 'children'.
    exports.h = function (selector) {
        var properties = arguments[1];
        if (typeof selector !== 'string') {
            throw new Error();
        }
        var childIndex = 1;
        if (properties && !properties.hasOwnProperty('vnodeSelector') && !Array.isArray(properties) && typeof properties === 'object') {
            childIndex = 2;
        } else {
            // Optional properties argument was omitted
            properties = undefined;
        }
        var text = undefined;
        var children = undefined;
        var argsLength = arguments.length;
        // Recognize a common special case where there is only a single text node
        if (argsLength === childIndex + 1) {
            var onlyChild = arguments[childIndex];
            if (typeof onlyChild === 'string') {
                text = onlyChild;
            } else if (onlyChild !== undefined && onlyChild !== null && onlyChild.length === 1 && typeof onlyChild[0] === 'string') {
                text = onlyChild[0];
            }
        }
        if (text === undefined) {
            children = [];
            for (; childIndex < arguments.length; childIndex++) {
                var child = arguments[childIndex];
                if (child === null || child === undefined) {
                    continue;
                } else if (Array.isArray(child)) {
                    appendChildren(selector, child, children);
                } else if (child.hasOwnProperty('vnodeSelector')) {
                    children.push(child);
                } else {
                    children.push(toTextVNode(child));
                }
            }
        }
        return {
            vnodeSelector: selector,
            properties: properties,
            children: children,
            text: text === '' ? undefined : text,
            domNode: null
        };
    };
    /**
 * Contains simple low-level utility functions to manipulate the real DOM.
 */
    exports.dom = {
        /**
     * Creates a real DOM tree from `vnode`. The [[Projection]] object returned will contain the resulting DOM Node in
     * its [[Projection.domNode|domNode]] property.
     * This is a low-level method. Users wil typically use a [[Projector]] instead.
     * @param vnode - The root of the virtual DOM tree that was created using the [[h]] function. NOTE: [[VNode]]
     * objects may only be rendered once.
     * @param projectionOptions - Options to be used to create and update the projection.
     * @returns The [[Projection]] which also contains the DOM Node that was created.
     */
        create: function (vnode, projectionOptions) {
            projectionOptions = applyDefaultProjectionOptions(projectionOptions);
            createDom(vnode, document.createElement('div'), undefined, projectionOptions);
            return createProjection(vnode, projectionOptions);
        },
        /**
     * Appends a new childnode to the DOM which is generated from a [[VNode]].
     * This is a low-level method. Users wil typically use a [[Projector]] instead.
     * @param parentNode - The parent node for the new childNode.
     * @param vnode - The root of the virtual DOM tree that was created using the [[h]] function. NOTE: [[VNode]]
     * objects may only be rendered once.
     * @param projectionOptions - Options to be used to create and update the [[Projection]].
     * @returns The [[Projection]] that was created.
     */
        append: function (parentNode, vnode, projectionOptions) {
            projectionOptions = applyDefaultProjectionOptions(projectionOptions);
            createDom(vnode, parentNode, undefined, projectionOptions);
            return createProjection(vnode, projectionOptions);
        },
        /**
     * Inserts a new DOM node which is generated from a [[VNode]].
     * This is a low-level method. Users wil typically use a [[Projector]] instead.
     * @param beforeNode - The node that the DOM Node is inserted before.
     * @param vnode - The root of the virtual DOM tree that was created using the [[h]] function.
     * NOTE: [[VNode]] objects may only be rendered once.
     * @param projectionOptions - Options to be used to create and update the projection, see [[createProjector]].
     * @returns The [[Projection]] that was created.
     */
        insertBefore: function (beforeNode, vnode, projectionOptions) {
            projectionOptions = applyDefaultProjectionOptions(projectionOptions);
            createDom(vnode, beforeNode.parentNode, beforeNode, projectionOptions);
            return createProjection(vnode, projectionOptions);
        },
        /**
     * Merges a new DOM node which is generated from a [[VNode]] with an existing DOM Node.
     * This means that the virtual DOM and the real DOM will have one overlapping element.
     * Therefore the selector for the root [[VNode]] will be ignored, but its properties and children will be applied to the Element provided.
     * This is a low-level method. Users wil typically use a [[Projector]] instead.
     * @param domNode - The existing element to adopt as the root of the new virtual DOM. Existing attributes and childnodes are preserved.
     * @param vnode - The root of the virtual DOM tree that was created using the [[h]] function. NOTE: [[VNode]] objects
     * may only be rendered once.
     * @param projectionOptions - Options to be used to create and update the projection, see [[createProjector]].
     * @returns The [[Projection]] that was created.
     */
        merge: function (element, vnode, projectionOptions) {
            projectionOptions = applyDefaultProjectionOptions(projectionOptions);
            vnode.domNode = element;
            initPropertiesAndChildren(element, vnode, projectionOptions);
            return createProjection(vnode, projectionOptions);
        }
    };
    /**
 * Creates a [[CalculationCache]] object, useful for caching [[VNode]] trees.
 * In practice, caching of [[VNode]] trees is not needed, because achieving 60 frames per second is almost never a problem.
 * For more information, see [[CalculationCache]].
 *
 * @param <Result> The type of the value that is cached.
 */
    exports.createCache = function () {
        var cachedInputs = undefined;
        var cachedOutcome = undefined;
        var result = {
            invalidate: function () {
                cachedOutcome = undefined;
                cachedInputs = undefined;
            },
            result: function (inputs, calculation) {
                if (cachedInputs) {
                    for (var i = 0; i < inputs.length; i++) {
                        if (cachedInputs[i] !== inputs[i]) {
                            cachedOutcome = undefined;
                        }
                    }
                }
                if (!cachedOutcome) {
                    cachedOutcome = calculation();
                    cachedInputs = inputs;
                }
                return cachedOutcome;
            }
        };
        return result;
    };
    /**
 * Creates a {@link Mapping} instance that keeps an array of result objects synchronized with an array of source objects.
 * See {@link http://maquettejs.org/docs/arrays.html|Working with arrays}.
 *
 * @param <Source>       The type of source items. A database-record for instance.
 * @param <Target>       The type of target items. A [[Component]] for instance.
 * @param getSourceKey   `function(source)` that must return a key to identify each source object. The result must either be a string or a number.
 * @param createResult   `function(source, index)` that must create a new result object from a given source. This function is identical
 *                       to the `callback` argument in `Array.map(callback)`.
 * @param updateResult   `function(source, target, index)` that updates a result to an updated source.
 */
    exports.createMapping = function (getSourceKey, createResult, updateResult) {
        var keys = [];
        var results = [];
        return {
            results: results,
            map: function (newSources) {
                var newKeys = newSources.map(getSourceKey);
                var oldTargets = results.slice();
                var oldIndex = 0;
                for (var i = 0; i < newSources.length; i++) {
                    var source = newSources[i];
                    var sourceKey = newKeys[i];
                    if (sourceKey === keys[oldIndex]) {
                        results[i] = oldTargets[oldIndex];
                        updateResult(source, oldTargets[oldIndex], i);
                        oldIndex++;
                    } else {
                        var found = false;
                        for (var j = 1; j < keys.length; j++) {
                            var searchIndex = (oldIndex + j) % keys.length;
                            if (keys[searchIndex] === sourceKey) {
                                results[i] = oldTargets[searchIndex];
                                updateResult(newSources[i], oldTargets[searchIndex], i);
                                oldIndex = searchIndex + 1;
                                found = true;
                                break;
                            }
                        }
                        if (!found) {
                            results[i] = createResult(source, i);
                        }
                    }
                }
                results.length = newSources.length;
                keys = newKeys;
            }
        };
    };
    /**
 * Creates a [[Projector]] instance using the provided projectionOptions.
 *
 * For more information, see [[Projector]].
 *
 * @param projectionOptions   Options that influence how the DOM is rendered and updated.
 */
    exports.createProjector = function (projectorOptions) {
        var projector;
        var projectionOptions = applyDefaultProjectionOptions(projectorOptions);
        projectionOptions.eventHandlerInterceptor = function (propertyName, eventHandler, domNode, properties) {
            return function () {
                // intercept function calls (event handlers) to do a render afterwards.
                projector.scheduleRender();
                return eventHandler.apply(properties.bind || this, arguments);
            };
        };
        var renderCompleted = true;
        var scheduled;
        var stopped = false;
        var projections = [];
        var renderFunctions = [];
        // matches the projections array
        var doRender = function () {
            scheduled = undefined;
            if (!renderCompleted) {
                return;    // The last render threw an error, it should be logged in the browser console.
            }
            var s = Date.now()
            renderCompleted = false;
            for (var i = 0; i < projections.length; i++) {
                var updatedVnode = renderFunctions[i]();
                projections[i].update(updatedVnode);
            }
            if (Date.now()-s > 15)
                console.log("Render time:", Date.now()-s, "ms")
            renderCompleted = true;
        };
        projector = {
            scheduleRender: function () {
                if (!scheduled && !stopped) {
                    scheduled = requestAnimationFrame(doRender);
                }
            },
            stop: function () {
                if (scheduled) {
                    cancelAnimationFrame(scheduled);
                    scheduled = undefined;
                }
                stopped = true;
            },
            resume: function () {
                stopped = false;
                renderCompleted = true;
                projector.scheduleRender();
            },
            append: function (parentNode, renderMaquetteFunction) {
                projections.push(exports.dom.append(parentNode, renderMaquetteFunction(), projectionOptions));
                renderFunctions.push(renderMaquetteFunction);
            },
            insertBefore: function (beforeNode, renderMaquetteFunction) {
                projections.push(exports.dom.insertBefore(beforeNode, renderMaquetteFunction(), projectionOptions));
                renderFunctions.push(renderMaquetteFunction);
            },
            merge: function (domNode, renderMaquetteFunction) {
                projections.push(exports.dom.merge(domNode, renderMaquetteFunction(), projectionOptions));
                renderFunctions.push(renderMaquetteFunction);
            },
            replace: function (domNode, renderMaquetteFunction) {
                var vnode = renderMaquetteFunction();
                createDom(vnode, domNode.parentNode, domNode, projectionOptions);
                domNode.parentNode.removeChild(domNode);
                projections.push(createProjection(vnode, projectionOptions));
                renderFunctions.push(renderMaquetteFunction);
            },
            detach: function (renderMaquetteFunction) {
                for (var i = 0; i < renderFunctions.length; i++) {
                    if (renderFunctions[i] === renderMaquetteFunction) {
                        renderFunctions.splice(i, 1);
                        return projections.splice(i, 1)[0];
                    }
                }
                throw new Error('renderMaquetteFunction was not found');
            }
        };
        return projector;
    };
}));