`\n * ```\n *\n * When `repeat` is invoked, it returns a directive function that closes over\n * `items` and the template function. When the outer template is rendered, the\n * return directive function is called with the Part for the expression.\n * `repeat` then performs it's custom logic to render multiple items.\n *\n * @param f The directive factory function. Must be a function that returns a\n * function of the signature `(part: Part) => void`. The returned function will\n * be called with the part object.\n *\n * @example\n *\n * import {directive, html} from 'lit-html';\n *\n * const immutable = directive((v) => (part) => {\n * if (part.value !== v) {\n * part.setValue(v)\n * }\n * });\n */\nexport const directive = (f: F): F =>\n ((...args: unknown[]) => {\n const d = f(...args);\n directives.set(d, true);\n return d;\n }) as F;\n\nexport const isDirective = (o: unknown): o is DirectiveFn => {\n return typeof o === 'function' && directives.has(o);\n};\n","/**\n * @license\n * Copyright (c) 2018 The Polymer Project Authors. All rights reserved.\n * This code may only be used under the BSD style license found at\n * http://polymer.github.io/LICENSE.txt\n * The complete set of authors may be found at\n * http://polymer.github.io/AUTHORS.txt\n * The complete set of contributors may be found at\n * http://polymer.github.io/CONTRIBUTORS.txt\n * Code distributed by Google as part of the polymer project is also\n * subject to an additional IP rights grant found at\n * http://polymer.github.io/PATENTS.txt\n */\n\n/**\n * The Part interface represents a dynamic part of a template instance rendered\n * by lit-html.\n */\nexport interface Part {\n readonly value: unknown;\n\n /**\n * Sets the current part value, but does not write it to the DOM.\n * @param value The value that will be committed.\n */\n setValue(value: unknown): void;\n\n /**\n * Commits the current part value, causing it to actually be written to the\n * DOM.\n *\n * Directives are run at the start of `commit`, so that if they call\n * `part.setValue(...)` synchronously that value will be used in the current\n * commit, and there's no need to call `part.commit()` within the directive.\n * If directives set a part value asynchronously, then they must call\n * `part.commit()` manually.\n */\n commit(): void;\n}\n\n/**\n * A sentinel value that signals that a value was handled by a directive and\n * should not be written to the DOM.\n */\nexport const noChange = {};\n\n/**\n * A sentinel value that signals a NodePart to fully clear its content.\n */\nexport const nothing = {};\n","/**\n * @license\n * Copyright (c) 2017 The Polymer Project Authors. All rights reserved.\n * This code may only be used under the BSD style license found at\n * http://polymer.github.io/LICENSE.txt\n * The complete set of authors may be found at\n * http://polymer.github.io/AUTHORS.txt\n * The complete set of contributors may be found at\n * http://polymer.github.io/CONTRIBUTORS.txt\n * Code distributed by Google as part of the polymer project is also\n * subject to an additional IP rights grant found at\n * http://polymer.github.io/PATENTS.txt\n */\n\nimport {isCEPolyfill} from './dom.js';\nimport {Part} from './part.js';\nimport {RenderOptions} from './render-options.js';\nimport {TemplateProcessor} from './template-processor.js';\nimport {isTemplatePartActive, Template, TemplatePart} from './template.js';\n\n/**\n * An instance of a `Template` that can be attached to the DOM and updated\n * with new values.\n */\nexport class TemplateInstance {\n private readonly __parts: Array = [];\n readonly processor: TemplateProcessor;\n readonly options: RenderOptions;\n readonly template: Template;\n\n constructor(\n template: Template, processor: TemplateProcessor,\n options: RenderOptions) {\n this.template = template;\n this.processor = processor;\n this.options = options;\n }\n\n update(values: readonly unknown[]) {\n let i = 0;\n for (const part of this.__parts) {\n if (part !== undefined) {\n part.setValue(values[i]);\n }\n i++;\n }\n for (const part of this.__parts) {\n if (part !== undefined) {\n part.commit();\n }\n }\n }\n\n _clone(): DocumentFragment {\n // There are a number of steps in the lifecycle of a template instance's\n // DOM fragment:\n // 1. Clone - create the instance fragment\n // 2. Adopt - adopt into the main document\n // 3. Process - find part markers and create parts\n // 4. Upgrade - upgrade custom elements\n // 5. Update - set node, attribute, property, etc., values\n // 6. Connect - connect to the document. Optional and outside of this\n // method.\n //\n // We have a few constraints on the ordering of these steps:\n // * We need to upgrade before updating, so that property values will pass\n // through any property setters.\n // * We would like to process before upgrading so that we're sure that the\n // cloned fragment is inert and not disturbed by self-modifying DOM.\n // * We want custom elements to upgrade even in disconnected fragments.\n //\n // Given these constraints, with full custom elements support we would\n // prefer the order: Clone, Process, Adopt, Upgrade, Update, Connect\n //\n // But Safari does not implement CustomElementRegistry#upgrade, so we\n // can not implement that order and still have upgrade-before-update and\n // upgrade disconnected fragments. So we instead sacrifice the\n // process-before-upgrade constraint, since in Custom Elements v1 elements\n // must not modify their light DOM in the constructor. We still have issues\n // when co-existing with CEv0 elements like Polymer 1, and with polyfills\n // that don't strictly adhere to the no-modification rule because shadow\n // DOM, which may be created in the constructor, is emulated by being placed\n // in the light DOM.\n //\n // The resulting order is on native is: Clone, Adopt, Upgrade, Process,\n // Update, Connect. document.importNode() performs Clone, Adopt, and Upgrade\n // in one step.\n //\n // The Custom Elements v1 polyfill supports upgrade(), so the order when\n // polyfilled is the more ideal: Clone, Process, Adopt, Upgrade, Update,\n // Connect.\n\n const fragment = isCEPolyfill ?\n this.template.element.content.cloneNode(true) as DocumentFragment :\n document.importNode(this.template.element.content, true);\n\n const stack: Node[] = [];\n const parts = this.template.parts;\n // Edge needs all 4 parameters present; IE11 needs 3rd parameter to be null\n const walker = document.createTreeWalker(\n fragment,\n 133 /* NodeFilter.SHOW_{ELEMENT|COMMENT|TEXT} */,\n null,\n false);\n let partIndex = 0;\n let nodeIndex = 0;\n let part: TemplatePart;\n let node = walker.nextNode();\n // Loop through all the nodes and parts of a template\n while (partIndex < parts.length) {\n part = parts[partIndex];\n if (!isTemplatePartActive(part)) {\n this.__parts.push(undefined);\n partIndex++;\n continue;\n }\n\n // Progress the tree walker until we find our next part's node.\n // Note that multiple parts may share the same node (attribute parts\n // on a single element), so this loop may not run at all.\n while (nodeIndex < part.index) {\n nodeIndex++;\n if (node!.nodeName === 'TEMPLATE') {\n stack.push(node!);\n walker.currentNode = (node as HTMLTemplateElement).content;\n }\n if ((node = walker.nextNode()) === null) {\n // We've exhausted the content inside a nested template element.\n // Because we still have parts (the outer for-loop), we know:\n // - There is a template in the stack\n // - The walker will find a nextNode outside the template\n walker.currentNode = stack.pop()!;\n node = walker.nextNode();\n }\n }\n\n // We've arrived at our part's node.\n if (part.type === 'node') {\n const part = this.processor.handleTextExpression(this.options);\n part.insertAfterNode(node!.previousSibling!);\n this.__parts.push(part);\n } else {\n this.__parts.push(...this.processor.handleAttributeExpressions(\n node as Element, part.name, part.strings, this.options));\n }\n partIndex++;\n }\n\n if (isCEPolyfill) {\n document.adoptNode(fragment);\n customElements.upgrade(fragment);\n }\n return fragment;\n }\n}\n","/**\n * @license\n * Copyright (c) 2017 The Polymer Project Authors. All rights reserved.\n * This code may only be used under the BSD style license found at\n * http://polymer.github.io/LICENSE.txt\n * The complete set of authors may be found at\n * http://polymer.github.io/AUTHORS.txt\n * The complete set of contributors may be found at\n * http://polymer.github.io/CONTRIBUTORS.txt\n * Code distributed by Google as part of the polymer project is also\n * subject to an additional IP rights grant found at\n * http://polymer.github.io/PATENTS.txt\n */\n\n/**\n * @module lit-html\n */\n\nimport {reparentNodes} from './dom.js';\nimport {TemplateProcessor} from './template-processor.js';\nimport {boundAttributeSuffix, lastAttributeNameRegex, marker, nodeMarker} from './template.js';\n\ndeclare const trustedTypes: typeof window.trustedTypes;\n/**\n * Our TrustedTypePolicy for HTML which is declared using the html template\n * tag function.\n *\n * That HTML is a developer-authored constant, and is parsed with innerHTML\n * before any untrusted expressions have been mixed in. Therefor it is\n * considered safe by construction.\n */\nconst policy = window.trustedTypes &&\n trustedTypes!.createPolicy('lit-html', {createHTML: (s) => s});\n\nconst commentMarker = ` ${marker} `;\n\n/**\n * The return type of `html`, which holds a Template and the values from\n * interpolated expressions.\n */\nexport class TemplateResult {\n readonly strings: TemplateStringsArray;\n readonly values: readonly unknown[];\n readonly type: string;\n readonly processor: TemplateProcessor;\n\n constructor(\n strings: TemplateStringsArray, values: readonly unknown[], type: string,\n processor: TemplateProcessor) {\n this.strings = strings;\n this.values = values;\n this.type = type;\n this.processor = processor;\n }\n\n /**\n * Returns a string of HTML used to create a `` element.\n */\n getHTML(): string {\n const l = this.strings.length - 1;\n let html = '';\n let isCommentBinding = false;\n\n for (let i = 0; i < l; i++) {\n const s = this.strings[i];\n // For each binding we want to determine the kind of marker to insert\n // into the template source before it's parsed by the browser's HTML\n // parser. The marker type is based on whether the expression is in an\n // attribute, text, or comment position.\n // * For node-position bindings we insert a comment with the marker\n // sentinel as its text content, like .\n // * For attribute bindings we insert just the marker sentinel for the\n // first binding, so that we support unquoted attribute bindings.\n // Subsequent bindings can use a comment marker because multi-binding\n // attributes must be quoted.\n // * For comment bindings we insert just the marker sentinel so we don't\n // close the comment.\n //\n // The following code scans the template source, but is *not* an HTML\n // parser. We don't need to track the tree structure of the HTML, only\n // whether a binding is inside a comment, and if not, if it appears to be\n // the first binding in an attribute.\n const commentOpen = s.lastIndexOf('', commentOpen + 1) === -1;\n // Check to see if we have an attribute-like sequence preceding the\n // expression. This can match \"name=value\" like structures in text,\n // comments, and attribute values, so there can be false-positives.\n const attributeMatch = lastAttributeNameRegex.exec(s);\n if (attributeMatch === null) {\n // We're only in this branch if we don't have a attribute-like\n // preceding sequence. For comments, this guards against unusual\n // attribute values like
. Cases like\n // are handled correctly in the attribute branch\n // below.\n html += s + (isCommentBinding ? commentMarker : nodeMarker);\n } else {\n // For attributes we use just a marker sentinel, and also append a\n // $lit$ suffix to the name to opt-out of attribute-specific parsing\n // that IE and Edge do for style and certain SVG attributes.\n html += s.substr(0, attributeMatch.index) + attributeMatch[1] +\n attributeMatch[2] + boundAttributeSuffix + attributeMatch[3] +\n marker;\n }\n }\n html += this.strings[l];\n return html;\n }\n\n getTemplateElement(): HTMLTemplateElement {\n const template = document.createElement('template');\n let value = this.getHTML();\n if (policy !== undefined) {\n // this is secure because `this.strings` is a TemplateStringsArray.\n // TODO: validate this when\n // https://github.com/tc39/proposal-array-is-template-object is\n // implemented.\n value = policy.createHTML(value) as unknown as string;\n }\n template.innerHTML = value;\n return template;\n }\n}\n\n/**\n * A TemplateResult for SVG fragments.\n *\n * This class wraps HTML in an `