{"version":3,"file":"class-map.js","sources":["../../src/directives/class-map.ts"],"sourcesContent":["/**\n * @license\n * Copyright 2018 Google LLC\n * SPDX-License-Identifier: BSD-3-Clause\n */\n\nimport {AttributePart, noChange} from '../lit-html.js';\nimport {\n  directive,\n  Directive,\n  DirectiveParameters,\n  PartInfo,\n  PartType,\n} from '../directive.js';\n\n/**\n * A key-value set of class names to truthy values.\n */\nexport interface ClassInfo {\n  readonly [name: string]: string | boolean | number;\n}\n\nclass ClassMapDirective extends Directive {\n  /**\n   * Stores the ClassInfo object applied to a given AttributePart.\n   * Used to unset existing values when a new ClassInfo object is applied.\n   */\n  private _previousClasses?: Set<string>;\n  private _staticClasses?: Set<string>;\n\n  constructor(partInfo: PartInfo) {\n    super(partInfo);\n    if (\n      partInfo.type !== PartType.ATTRIBUTE ||\n      partInfo.name !== 'class' ||\n      (partInfo.strings?.length as number) > 2\n    ) {\n      throw new Error(\n        '`classMap()` can only be used in the `class` attribute ' +\n          'and must be the only part in the attribute.'\n      );\n    }\n  }\n\n  render(classInfo: ClassInfo) {\n    // Add spaces to ensure separation from static classes\n    return (\n      ' ' +\n      Object.keys(classInfo)\n        .filter((key) => classInfo[key])\n        .join(' ') +\n      ' '\n    );\n  }\n\n  override update(part: AttributePart, [classInfo]: DirectiveParameters<this>) {\n    // Remember dynamic classes on the first render\n    if (this._previousClasses === undefined) {\n      this._previousClasses = new Set();\n      if (part.strings !== undefined) {\n        this._staticClasses = new Set(\n          part.strings\n            .join(' ')\n            .split(/\\s/)\n            .filter((s) => s !== '')\n        );\n      }\n      for (const name in classInfo) {\n        if (classInfo[name] && !this._staticClasses?.has(name)) {\n          this._previousClasses.add(name);\n        }\n      }\n      return this.render(classInfo);\n    }\n\n    const classList = part.element.classList;\n\n    // Remove old classes that no longer apply\n    for (const name of this._previousClasses) {\n      if (!(name in classInfo)) {\n        classList.remove(name);\n        this._previousClasses!.delete(name);\n      }\n    }\n\n    // Add or remove classes based on their classMap value\n    for (const name in classInfo) {\n      // We explicitly want a loose truthy check of `value` because it seems\n      // more convenient that '' and 0 are skipped.\n      const value = !!classInfo[name];\n      if (\n        value !== this._previousClasses.has(name) &&\n        !this._staticClasses?.has(name)\n      ) {\n        if (value) {\n          classList.add(name);\n          this._previousClasses.add(name);\n        } else {\n          classList.remove(name);\n          this._previousClasses.delete(name);\n        }\n      }\n    }\n    return noChange;\n  }\n}\n\n/**\n * A directive that applies dynamic CSS classes.\n *\n * This must be used in the `class` attribute and must be the only part used in\n * the attribute. It takes each property in the `classInfo` argument and adds\n * the property name to the element's `classList` if the property value is\n * truthy; if the property value is falsey, the property name is removed from\n * the element's `class`.\n *\n * For example `{foo: bar}` applies the class `foo` if the value of `bar` is\n * truthy.\n *\n * @param classInfo\n */\nexport const classMap = directive(ClassMapDirective);\n\n/**\n * The type of the class that powers this directive. Necessary for naming the\n * directive's return type.\n */\nexport type {ClassMapDirective};\n"],"names":["classMap","directive","Directive","constructor","partInfo","super","type","PartType","ATTRIBUTE","name","strings","length","Error","render","classInfo","Object","keys","filter","key","join","update","part","undefined","this","_previousClasses","Set","_staticClasses","split","s","has","add","classList","element","remove","delete","value","noChange"],"mappings":";;;;;SAyHaA,EAAWC,EAnGxB,cAAgCC,EAQ9B,WAAAC,CAAYC,GAEV,GADAC,MAAMD,GAEJA,EAASE,OAASC,EAASC,WACT,UAAlBJ,EAASK,MACRL,EAASM,SAASC,OAAoB,EAEvC,MAAUC,MACR,qGAIL,CAED,MAAAC,CAAOC,GAEL,MACE,IACAC,OAAOC,KAAKF,GACTG,QAAQC,GAAQJ,EAAUI,KAC1BC,KAAK,KACR,GAEH,CAEQ,MAAAC,CAAOC,GAAsBP,IAEpC,QAA8BQ,IAA1BC,KAAKC,GAAgC,CACvCD,KAAKC,GAAmB,IAAIC,SACPH,IAAjBD,EAAKX,UACPa,KAAKG,GAAiB,IAAID,IACxBJ,EAAKX,QACFS,KAAK,KACLQ,MAAM,MACNV,QAAQW,GAAY,KAANA,MAGrB,IAAK,MAAMnB,KAAQK,EACbA,EAAUL,KAAUc,KAAKG,IAAgBG,IAAIpB,IAC/Cc,KAAKC,GAAiBM,IAAIrB,GAG9B,OAAOc,KAAKV,OAAOC,EACpB,CAED,MAAMiB,EAAYV,EAAKW,QAAQD,UAG/B,IAAK,MAAMtB,KAAQc,KAAKC,GAChBf,KAAQK,IACZiB,EAAUE,OAAOxB,GACjBc,KAAKC,GAAkBU,OAAOzB,IAKlC,IAAK,MAAMA,KAAQK,EAAW,CAG5B,MAAMqB,IAAUrB,EAAUL,GAExB0B,IAAUZ,KAAKC,GAAiBK,IAAIpB,IACnCc,KAAKG,IAAgBG,IAAIpB,KAEtB0B,GACFJ,EAAUD,IAAIrB,GACdc,KAAKC,GAAiBM,IAAIrB,KAE1BsB,EAAUE,OAAOxB,GACjBc,KAAKC,GAAiBU,OAAOzB,IAGlC,CACD,OAAO2B,CACR"}