angular-docs-cn/packages/language-service/ivy/testing/src/util.ts

/**
 * @license
 * Copyright Google LLC 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
 */

/**
 * Given a text snippet which contains exactly one cursor symbol ('¦'), extract both the offset of
 * that cursor within the text as well as the text snippet without the cursor.
 */
export function extractCursorInfo(textWithCursor: string): {cursor: number, text: string} {
  const cursor = textWithCursor.indexOf('¦');
  if (cursor === -1 || textWithCursor.indexOf('¦', cursor + 1) !== -1) {
    throw new Error(`Expected to find exactly one cursor symbol '¦'`);
  }

  return {
    cursor,
    text: textWithCursor.substr(0, cursor) + textWithCursor.substr(cursor + 1),
  };
}

function last<T>(array: T[]): T {
  if (array.length === 0) {
    throw new Error(`last() called on empty array`);
  }
  return array[array.length - 1];
}

/**
 * Expect that a list of objects with a `fileName` property matches a set of expected files by only
 * comparing the file names and not any path prefixes.
 *
 * This assertion is independent of the order of either list.
 */
export function assertFileNames(refs: Array<{fileName: string}>, expectedFileNames: string[]) {
  const actualPaths = refs.map(r => r.fileName);
  const actualFileNames = actualPaths.map(p => last(p.split('/')));
  expect(new Set(actualFileNames)).toEqual(new Set(expectedFileNames));
}

/**
 * Returns whether the given `ts.Diagnostic` is of a type only produced by the Angular compiler (as
 * opposed to being an upstream TypeScript diagnostic).
 *
 * Template type-checking diagnostics are not "ng-specific" in this sense, since they are plain
 * TypeScript diagnostics that are produced from expressions in the template by way of a TCB.
 */
export function isNgSpecificDiagnostic(diag: ts.Diagnostic): boolean {
  // Angular-specific diagnostics use a negative code space.
  return diag.code < 0;
}