angular-docs-cn/packages/compiler/test/ml_parser/ast_serializer_spec.ts

/**
 * @license
 * Copyright Google Inc. All Rights Reserved.
 *
 * Use of this source code is governed by an MIT-style license that can be
 * found in the LICENSE file at https://angular.io/license
 */

import * as html from '@angular/compiler/src/ml_parser/ast';
import {HtmlParser} from '@angular/compiler/src/ml_parser/html_parser';
import {getHtmlTagDefinition} from '@angular/compiler/src/ml_parser/html_tags';

export function main() {
  describe('Node serializer', () => {
    let parser: HtmlParser;

    beforeEach(() => { parser = new HtmlParser(); });

    it('should support element', () => {
      const html = '<p></p>';
      const ast = parser.parse(html, 'url');
      expect(serializeNodes(ast.rootNodes)).toEqual([html]);
    });

    it('should support attributes', () => {
      const html = '<p k="value"></p>';
      const ast = parser.parse(html, 'url');
      expect(serializeNodes(ast.rootNodes)).toEqual([html]);
    });

    it('should support text', () => {
      const html = 'some text';
      const ast = parser.parse(html, 'url');
      expect(serializeNodes(ast.rootNodes)).toEqual([html]);
    });

    it('should support expansion', () => {
      const html = '{number, plural, =0 {none} =1 {one} other {many}}';
      const ast = parser.parse(html, 'url', true);
      expect(serializeNodes(ast.rootNodes)).toEqual([html]);
    });

    it('should support comment', () => {
      const html = '<!--comment-->';
      const ast = parser.parse(html, 'url', true);
      expect(serializeNodes(ast.rootNodes)).toEqual([html]);
    });

    it('should support nesting', () => {
      const html = `<div i18n="meaning|desc">
        <span>{{ interpolation }}</span>
        <!--comment-->
        <p expansion="true">
          {number, plural, =0 {{sex, select, other {<b>?</b>}}}}
        </p>                            
      </div>`;
      const ast = parser.parse(html, 'url', true);
      expect(serializeNodes(ast.rootNodes)).toEqual([html]);
    });
  });
}

class _SerializerVisitor implements html.Visitor {
  visitElement(element: html.Element, context: any): any {
    if (getHtmlTagDefinition(element.name).isVoid) {
      return `<${element.name}${this._visitAll(element.attrs, ' ')}/>`;
    }

    return `<${element.name}${this._visitAll(element.attrs, ' ')}>${this._visitAll(element.children)}</${element.name}>`;
  }

  visitAttribute(attribute: html.Attribute, context: any): any {
    return `${attribute.name}="${attribute.value}"`;
  }

  visitText(text: html.Text, context: any): any { return text.value; }

  visitComment(comment: html.Comment, context: any): any { return `<!--${comment.value}-->`; }

  visitExpansion(expansion: html.Expansion, context: any): any {
    return `{${expansion.switchValue}, ${expansion.type},${this._visitAll(expansion.cases)}}`;
  }

  visitExpansionCase(expansionCase: html.ExpansionCase, context: any): any {
    return ` ${expansionCase.value} {${this._visitAll(expansionCase.expression)}}`;
  }

  private _visitAll(nodes: html.Node[], join: string = ''): string {
    if (nodes.length == 0) {
      return '';
    }
    return join + nodes.map(a => a.visit(this, null)).join(join);
  }
}

const serializerVisitor = new _SerializerVisitor();

export function serializeNodes(nodes: html.Node[]): string[] {
  return nodes.map(node => node.visit(serializerVisitor, null));
}