{"version":3,"file":"async-append.js","sourceRoot":"","sources":["../../src/directives/async-append.ts"],"names":[],"mappings":"AAAA;;;;GAIG;AAGH,OAAO,EACL,SAAS,EAGT,QAAQ,GACT,MAAM,iBAAiB,CAAC;AACzB,OAAO,EAAC,qBAAqB,EAAC,MAAM,oBAAoB,CAAC;AACzD,OAAO,EACL,SAAS,EACT,UAAU,EACV,iBAAiB,GAClB,MAAM,yBAAyB,CAAC;AAEjC,MAAM,oBAAqB,SAAQ,qBAAqB;IAGtD,0EAA0E;IAC1E,YAAY,QAAkB;QAC5B,KAAK,CAAC,QAAQ,CAAC,CAAC;QAChB,IAAI,QAAQ,CAAC,IAAI,KAAK,QAAQ,CAAC,KAAK,EAAE;YACpC,MAAM,IAAI,KAAK,CAAC,mDAAmD,CAAC,CAAC;SACtE;IACH,CAAC;IAED,yEAAyE;IAChE,MAAM,CAAC,IAAe,EAAE,MAAiC;QAChE,IAAI,CAAC,WAAW,GAAG,IAAI,CAAC;QACxB,OAAO,KAAK,CAAC,MAAM,CAAC,IAAI,EAAE,MAAM,CAAC,CAAC;IACpC,CAAC;IAED,sDAAsD;IACnC,WAAW,CAAC,KAAc,EAAE,KAAa;QAC1D,6DAA6D;QAC7D,kDAAkD;QAClD,IAAI,KAAK,KAAK,CAAC,EAAE;YACf,SAAS,CAAC,IAAI,CAAC,WAAW,CAAC,CAAC;SAC7B;QACD,mEAAmE;QACnE,MAAM,OAAO,GAAG,UAAU,CAAC,IAAI,CAAC,WAAW,CAAC,CAAC;QAC7C,iBAAiB,CAAC,OAAO,EAAE,KAAK,CAAC,CAAC;IACpC,CAAC;CACF;AAED;;;;;;;;;;;;;;;;;GAiBG;AACH,MAAM,CAAC,MAAM,WAAW,GAAG,SAAS,CAAC,oBAAoB,CAAC,CAAC","sourcesContent":["/**\n * @license\n * Copyright 2017 Google LLC\n * SPDX-License-Identifier: BSD-3-Clause\n */\n\nimport {ChildPart} from '../lit-html.js';\nimport {\n  directive,\n  DirectiveParameters,\n  PartInfo,\n  PartType,\n} from '../directive.js';\nimport {AsyncReplaceDirective} from './async-replace.js';\nimport {\n  clearPart,\n  insertPart,\n  setChildPartValue,\n} from '../directive-helpers.js';\n\nclass AsyncAppendDirective extends AsyncReplaceDirective {\n  private __childPart!: ChildPart;\n\n  // Override AsyncReplace to narrow the allowed part type to ChildPart only\n  constructor(partInfo: PartInfo) {\n    super(partInfo);\n    if (partInfo.type !== PartType.CHILD) {\n      throw new Error('asyncAppend can only be used in child expressions');\n    }\n  }\n\n  // Override AsyncReplace to save the part since we need to append into it\n  override update(part: ChildPart, params: DirectiveParameters<this>) {\n    this.__childPart = part;\n    return super.update(part, params);\n  }\n\n  // Override AsyncReplace to append rather than replace\n  protected override commitValue(value: unknown, index: number) {\n    // When we get the first value, clear the part. This lets the\n    // previous value display until we can replace it.\n    if (index === 0) {\n      clearPart(this.__childPart);\n    }\n    // Create and insert a new part and set its value to the next value\n    const newPart = insertPart(this.__childPart);\n    setChildPartValue(newPart, value);\n  }\n}\n\n/**\n * A directive that renders the items of an async iterable[1], appending new\n * values after previous values, similar to the built-in support for iterables.\n * This directive is usable only in child expressions.\n *\n * Async iterables are objects with a [Symbol.asyncIterator] method, which\n * returns an iterator who's `next()` method returns a Promise. When a new\n * value is available, the Promise resolves and the value is appended to the\n * Part controlled by the directive. If another value other than this\n * directive has been set on the Part, the iterable will no longer be listened\n * to and new values won't be written to the Part.\n *\n * [1]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/for-await...of\n *\n * @param value An async iterable\n * @param mapper An optional function that maps from (value, index) to another\n *     value. Useful for generating templates for each item in the iterable.\n */\nexport const asyncAppend = directive(AsyncAppendDirective);\n\n/**\n * The type of the class that powers this directive. Necessary for naming the\n * directive's return type.\n */\nexport type {AsyncAppendDirective};\n"]}