Function getComponentId

packages/core/src/render3/definition.ts:685–776

* A method can returns a component ID from the component definition using a variant of DJB2 hash * algorithm.

(componentDef: ComponentDef<T>)

 * algorithm.
 */
function getComponentId<T>(componentDef: ComponentDef<T>): string {
  let hash = 0;

  // For components with i18n in templates, the `consts` array is generated by the compiler
  // as a function. If client and server bundles were produced with different minification
  // configurations, the serializable contents of the function body would be different on
  // the client and on the server. This might result in different ids generated. To avoid this
  // issue, we do not take the `consts` contents into account if it's a function.
  // See https://github.com/angular/angular/issues/58713.
  const componentDefConsts = typeof componentDef.consts === 'function' ? '' : componentDef.consts;

  // We cannot rely solely on the component selector as the same selector can be used in different
  // modules.
  //
  // `componentDef.style` is not used, due to it causing inconsistencies. Ex: when server
  // component styles has no sourcemaps and browsers do.
  //
  // Example:
  // https://github.com/angular/components/blob/d9f82c8f95309e77a6d82fd574c65871e91354c2/src/material/core/option/option.ts#L248
  // https://github.com/angular/components/blob/285f46dc2b4c5b127d356cb7c4714b221f03ce50/src/material/legacy-core/option/option.ts#L32
  const hashSelectors = [
    componentDef.selectors,
    componentDef.ngContentSelectors,
    componentDef.hostVars,
    componentDef.hostAttrs,
    componentDefConsts,
    componentDef.vars,
    componentDef.decls,
    componentDef.encapsulation,
    componentDef.standalone,
    componentDef.signals,
    componentDef.exportAs,
    JSON.stringify(componentDef.inputs),
    JSON.stringify(componentDef.outputs),
    // We cannot use 'componentDef.type.name' as the name of the symbol will change and will not
    // match in the server and browser bundles.
    Object.getOwnPropertyNames(componentDef.type.prototype),
    !!componentDef.contentQueries,
    !!componentDef.viewQuery,
  ];

  if (typeof ngDevMode === 'undefined' || ngDevMode) {
    // If client and server bundles were produced with different minification configurations,
    // the serializable contents of the function body would be different on the client and on
    // the server. Ensure that we do not accidentally use functions in component id computation.
    for (const item of hashSelectors) {
      assertNotEqual(
        typeof item,
        'function',
        'Internal error: attempting to use a function in component id computation logic.',
      );
    }
  }

  for (const char of hashSelectors.join('|')) {
    hash = (Math.imul(31, hash) + char.charCodeAt(0)) << 0;
  }