angular-docs-cn/packages/compiler/test/expression_parser/parser_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 {ASTWithSource, BindingPipe, Interpolation, ParserError, TemplateBinding} from '@angular/compiler/src/expression_parser/ast';
import {Lexer} from '@angular/compiler/src/expression_parser/lexer';
import {Parser, SplitInterpolation, TemplateBindingParseResult} from '@angular/compiler/src/expression_parser/parser';
import {expect} from '@angular/platform-browser/testing/src/matchers';


import {unparse} from './utils/unparser';
import {validate} from './utils/validator';

describe('parser', () => {
  describe('parseAction', () => {
    it('should parse numbers', () => { checkAction('1'); });

    it('should parse strings', () => {
      checkAction('\'1\'', '"1"');
      checkAction('"1"');
    });

    it('should parse null', () => { checkAction('null'); });

    it('should parse undefined', () => { checkAction('undefined'); });

    it('should parse unary - expressions', () => {
      checkAction('-1', '0 - 1');
      checkAction('+1', '1 - 0');
      checkAction(`-'1'`, `0 - "1"`);
      checkAction(`+'1'`, `"1" - 0`);
    });

    it('should parse unary ! expressions', () => {
      checkAction('!true');
      checkAction('!!true');
      checkAction('!!!true');
    });

    it('should parse postfix ! expression', () => {
      checkAction('true!');
      checkAction('a!.b');
      checkAction('a!!!!.b');
    });

    it('should parse multiplicative expressions',
       () => { checkAction('3*4/2%5', '3 * 4 / 2 % 5'); });

    it('should parse additive expressions', () => { checkAction('3 + 6 - 2'); });

    it('should parse relational expressions', () => {
      checkAction('2 < 3');
      checkAction('2 > 3');
      checkAction('2 <= 2');
      checkAction('2 >= 2');
    });

    it('should parse equality expressions', () => {
      checkAction('2 == 3');
      checkAction('2 != 3');
    });

    it('should parse strict equality expressions', () => {
      checkAction('2 === 3');
      checkAction('2 !== 3');
    });

    it('should parse expressions', () => {
      checkAction('true && true');
      checkAction('true || false');
    });

    it('should parse grouped expressions', () => { checkAction('(1 + 2) * 3', '1 + 2 * 3'); });

    it('should ignore comments in expressions', () => { checkAction('a //comment', 'a'); });

    it('should retain // in string literals',
       () => { checkAction(`"http://www.google.com"`, `"http://www.google.com"`); });

    it('should parse an empty string', () => { checkAction(''); });

    describe('literals', () => {
      it('should parse array', () => {
        checkAction('[1][0]');
        checkAction('[[1]][0][0]');
        checkAction('[]');
        checkAction('[].length');
        checkAction('[1, 2].length');
      });

      it('should parse map', () => {
        checkAction('{}');
        checkAction('{a: 1, "b": 2}[2]');
        checkAction('{}["a"]');
      });

      it('should only allow identifier, string, or keyword as map key', () => {
        expectActionError('{(:0}', 'expected identifier, keyword, or string');
        expectActionError('{1234:0}', 'expected identifier, keyword, or string');
      });
    });

    describe('member access', () => {
      it('should parse field access', () => {
        checkAction('a');
        checkAction('this.a', 'a');
        checkAction('a.a');
      });

      it('should only allow identifier or keyword as member names', () => {
        expectActionError('x.(', 'identifier or keyword');
        expectActionError('x. 1234', 'identifier or keyword');
        expectActionError('x."foo"', 'identifier or keyword');
      });

      it('should parse safe field access', () => {
        checkAction('a?.a');
        checkAction('a.a?.a');
      });
    });

    describe('method calls', () => {
      it('should parse method calls', () => {
        checkAction('fn()');
        checkAction('add(1, 2)');
        checkAction('a.add(1, 2)');
        checkAction('fn().add(1, 2)');
      });
    });

    describe('functional calls', () => {
      it('should parse function calls', () => { checkAction('fn()(1, 2)'); });
    });

    describe('conditional', () => {
      it('should parse ternary/conditional expressions', () => {
        checkAction('7 == 3 + 4 ? 10 : 20');
        checkAction('false ? 10 : 20');
      });

      it('should report incorrect ternary operator syntax', () => {
        expectActionError('true?1', 'Conditional expression true?1 requires all 3 expressions');
      });
    });

    describe('assignment', () => {
      it('should support field assignments', () => {
        checkAction('a = 12');
        checkAction('a.a.a = 123');
        checkAction('a = 123; b = 234;');
      });

      it('should report on safe field assignments',
         () => { expectActionError('a?.a = 123', 'cannot be used in the assignment'); });

      it('should support array updates', () => { checkAction('a[0] = 200'); });
    });

    it('should error when using pipes',
       () => { expectActionError('x|blah', 'Cannot have a pipe'); });

    it('should store the source in the result',
       () => { expect(parseAction('someExpr', 'someExpr')); });

    it('should store the passed-in location',
       () => { expect(parseAction('someExpr', 'location').location).toBe('location'); });

    it('should report when encountering interpolation', () => {
      expectActionError('{{a()}}', 'Got interpolation ({{}}) where expression was expected');
    });
  });

  describe('general error handling', () => {
    it('should report an unexpected token',
       () => { expectActionError('[1,2] trac', 'Unexpected token \'trac\''); });

    it('should report reasonable error for unconsumed tokens',
       () => { expectActionError(')', 'Unexpected token ) at column 1 in [)]'); });

    it('should report a missing expected token', () => {
      expectActionError('a(b', 'Missing expected ) at the end of the expression [a(b]');
    });
  });

  describe('parseBinding', () => {
    describe('pipes', () => {
      it('should parse pipes', () => {
        checkBinding('a(b | c)', 'a((b | c))');
        checkBinding('a.b(c.d(e) | f)', 'a.b((c.d(e) | f))');
        checkBinding('[1, 2, 3] | a', '([1, 2, 3] | a)');
        checkBinding('{a: 1, "b": 2} | c', '({a: 1, "b": 2} | c)');
        checkBinding('a[b] | c', '(a[b] | c)');
        checkBinding('a?.b | c', '(a?.b | c)');
        checkBinding('true | a', '(true | a)');
        checkBinding('a | b:c | d', '((a | b:c) | d)');
        checkBinding('a | b:(c | d)', '(a | b:(c | d))');
      });

      it('should only allow identifier or keyword as formatter names', () => {
        expectBindingError('"Foo"|(', 'identifier or keyword');
        expectBindingError('"Foo"|1234', 'identifier or keyword');
        expectBindingError('"Foo"|"uppercase"', 'identifier or keyword');
      });

      it('should parse quoted expressions', () => { checkBinding('a:b', 'a:b'); });

      it('should not crash when prefix part is not tokenizable',
         () => { checkBinding('"a:b"', '"a:b"'); });

      it('should ignore whitespace around quote prefix', () => { checkBinding(' a :b', 'a:b'); });

      it('should refuse prefixes that are not single identifiers', () => {
        expectBindingError('a + b:c', '');
        expectBindingError('1:c', '');
      });
    });

    it('should store the source in the result',
       () => { expect(parseBinding('someExpr').source).toBe('someExpr'); });

    it('should store the passed-in location',
       () => { expect(parseBinding('someExpr', 'location').location).toBe('location'); });

    it('should report chain expressions',
       () => { expectError(parseBinding('1;2'), 'contain chained expression'); });

    it('should report assignment',
       () => { expectError(parseBinding('a=2'), 'contain assignments'); });

    it('should report when encountering interpolation', () => {
      expectBindingError('{{a.b}}', 'Got interpolation ({{}}) where expression was expected');
    });

    it('should parse conditional expression', () => { checkBinding('a < b ? a : b'); });

    it('should ignore comments in bindings', () => { checkBinding('a //comment', 'a'); });

    it('should retain // in string literals',
       () => { checkBinding(`"http://www.google.com"`, `"http://www.google.com"`); });

    it('should retain // in : microsyntax', () => { checkBinding('one:a//b', 'one:a//b'); });

  });

  describe('parseTemplateBindings', () => {

    function keys(templateBindings: any[]) { return templateBindings.map(binding => binding.key); }

    function keyValues(templateBindings: any[]) {
      return templateBindings.map(binding => {
        if (binding.keyIsVar) {
          return 'let ' + binding.key + (binding.name == null ? '=null' : '=' + binding.name);
        } else {
          return binding.key + (binding.expression == null ? '' : `=${binding.expression}`);
        }
      });
    }

    function keySpans(source: string, templateBindings: TemplateBinding[]) {
      return templateBindings.map(
          binding => source.substring(binding.span.start, binding.span.end));
    }

    function exprSources(templateBindings: any[]) {
      return templateBindings.map(
          binding => binding.expression != null ? binding.expression.source : null);
    }

    it('should parse a key without a value',
       () => { expect(keys(parseTemplateBindings('a', ''))).toEqual(['a']); });

    it('should allow string including dashes as keys', () => {
      let bindings = parseTemplateBindings('a', 'b');
      expect(keys(bindings)).toEqual(['a']);

      bindings = parseTemplateBindings('a-b', 'c');
      expect(keys(bindings)).toEqual(['a-b']);
    });

    it('should detect expressions as value', () => {
      let bindings = parseTemplateBindings('a', 'b');
      expect(exprSources(bindings)).toEqual(['b']);

      bindings = parseTemplateBindings('a', '1+1');
      expect(exprSources(bindings)).toEqual(['1+1']);
    });

    it('should detect names as value', () => {
      const bindings = parseTemplateBindings('a', 'let b');
      expect(keyValues(bindings)).toEqual(['a', 'let b=$implicit']);
    });

    it('should allow space and colon as separators', () => {
      let bindings = parseTemplateBindings('a', 'b');
      expect(keys(bindings)).toEqual(['a']);
      expect(exprSources(bindings)).toEqual(['b']);
    });

    it('should allow multiple pairs', () => {
      const bindings = parseTemplateBindings('a', '1 b 2');
      expect(keys(bindings)).toEqual(['a', 'aB']);
      expect(exprSources(bindings)).toEqual(['1 ', '2']);
    });

    it('should store the sources in the result', () => {
      const bindings = parseTemplateBindings('a', '1,b 2');
      expect(bindings[0].expression !.source).toEqual('1');
      expect(bindings[1].expression !.source).toEqual('2');
    });

    it('should store the passed-in location', () => {
      const bindings = parseTemplateBindings('a', '1,b 2', 'location');
      expect(bindings[0].expression !.location).toEqual('location');
    });

    it('should support let notation', () => {
      let bindings = parseTemplateBindings('key', 'let i');
      expect(keyValues(bindings)).toEqual(['key', 'let i=$implicit']);

      bindings = parseTemplateBindings('key', 'let a; let b');
      expect(keyValues(bindings)).toEqual([
        'key',
        'let a=$implicit',
        'let b=$implicit',
      ]);

      bindings = parseTemplateBindings('key', 'let a; let b;');
      expect(keyValues(bindings)).toEqual([
        'key',
        'let a=$implicit',
        'let b=$implicit',
      ]);

      bindings = parseTemplateBindings('key', 'let i-a = k-a');
      expect(keyValues(bindings)).toEqual([
        'key',
        'let i-a=k-a',
      ]);

      bindings = parseTemplateBindings('key', 'let item; let i = k');
      expect(keyValues(bindings)).toEqual([
        'key',
        'let item=$implicit',
        'let i=k',
      ]);

      bindings = parseTemplateBindings('directive', 'let item in expr; let a = b', 'location');
      expect(keyValues(bindings)).toEqual([
        'directive',
        'let item=$implicit',
        'directiveIn=expr in location',
        'let a=b',
      ]);
    });

    it('should support as notation', () => {
      let bindings = parseTemplateBindings('ngIf', 'exp as local', 'location');
      expect(keyValues(bindings)).toEqual(['ngIf=exp  in location', 'let local=ngIf']);

      bindings = parseTemplateBindings('ngFor', 'let item of items as iter; index as i', 'L');
      expect(keyValues(bindings)).toEqual([
        'ngFor', 'let item=$implicit', 'ngForOf=items  in L', 'let iter=ngForOf', 'let i=index'
      ]);
    });

    it('should parse pipes', () => {
      const bindings = parseTemplateBindings('key', 'value|pipe');
      const ast = bindings[0].expression !.ast;
      expect(ast).toBeAnInstanceOf(BindingPipe);
    });

    describe('spans', () => {
      it('should should support let', () => {
        const source = 'let i';
        expect(keySpans(source, parseTemplateBindings('key', 'let i'))).toEqual(['', 'let i']);
      });

      it('should support multiple lets', () => {
        const source = 'let item; let i=index; let e=even;';
        expect(keySpans(source, parseTemplateBindings('key', source))).toEqual([
          '', 'let item', 'let i=index', 'let e=even'
        ]);
      });

      it('should support a prefix', () => {
        const source = 'let person of people';
        const prefix = 'ngFor';
        const bindings = parseTemplateBindings(prefix, source);
        expect(keyValues(bindings)).toEqual([
          'ngFor', 'let person=$implicit', 'ngForOf=people in null'
        ]);
        expect(keySpans(source, bindings)).toEqual(['', 'let person ', 'of people']);
      });
    });
  });

  describe('parseInterpolation', () => {
    it('should return null if no interpolation',
       () => { expect(parseInterpolation('nothing')).toBe(null); });

    it('should parse no prefix/suffix interpolation', () => {
      const ast = parseInterpolation('{{a}}') !.ast as Interpolation;
      expect(ast.strings).toEqual(['', '']);
      expect(ast.expressions.length).toEqual(1);
      expect(ast.expressions[0].name).toEqual('a');
    });

    it('should parse prefix/suffix with multiple interpolation', () => {
      const originalExp = 'before {{ a }} middle {{ b }} after';
      const ast = parseInterpolation(originalExp) !.ast;
      expect(unparse(ast)).toEqual(originalExp);
      validate(ast);
    });

    it('should report empty interpolation expressions', () => {
      expectError(
          parseInterpolation('{{}}') !,
          'Blank expressions are not allowed in interpolated strings');

      expectError(
          parseInterpolation('foo {{  }}') !,
          'Parser Error: Blank expressions are not allowed in interpolated strings');
    });

    it('should parse conditional expression', () => { checkInterpolation('{{ a < b ? a : b }}'); });

    it('should parse expression with newline characters', () => {
      checkInterpolation(`{{ 'foo' +\n 'bar' +\r 'baz' }}`, `{{ "foo" + "bar" + "baz" }}`);
    });

    it('should support custom interpolation', () => {
      const parser = new Parser(new Lexer());
      const ast = parser.parseInterpolation('{% a %}', null, {start: '{%', end: '%}'}) !.ast as any;
      expect(ast.strings).toEqual(['', '']);
      expect(ast.expressions.length).toEqual(1);
      expect(ast.expressions[0].name).toEqual('a');
    });

    describe('comments', () => {
      it('should ignore comments in interpolation expressions',
         () => { checkInterpolation('{{a //comment}}', '{{ a }}'); });

      it('should retain // in single quote strings', () => {
        checkInterpolation(`{{ 'http://www.google.com' }}`, `{{ "http://www.google.com" }}`);
      });

      it('should retain // in double quote strings', () => {
        checkInterpolation(`{{ "http://www.google.com" }}`, `{{ "http://www.google.com" }}`);
      });

      it('should ignore comments after string literals',
         () => { checkInterpolation(`{{ "a//b" //comment }}`, `{{ "a//b" }}`); });

      it('should retain // in complex strings', () => {
        checkInterpolation(
            `{{"//a\'//b\`//c\`//d\'//e" //comment}}`, `{{ "//a\'//b\`//c\`//d\'//e" }}`);
      });

      it('should retain // in nested, unterminated strings',
         () => { checkInterpolation(`{{ "a\'b\`" //comment}}`, `{{ "a\'b\`" }}`); });
    });

  });

  describe('parseSimpleBinding', () => {
    it('should parse a field access', () => {
      const p = parseSimpleBinding('name');
      expect(unparse(p)).toEqual('name');
      validate(p);
    });

    it('should report when encountering pipes', () => {
      expectError(
          validate(parseSimpleBinding('a | somePipe')),
          'Host binding expression cannot contain pipes');
    });

    it('should report when encountering interpolation', () => {
      expectError(
          validate(parseSimpleBinding('{{exp}}')),
          'Got interpolation ({{}}) where expression was expected');
    });

    it('should report when encountering field write', () => {
      expectError(validate(parseSimpleBinding('a = b')), 'Bindings cannot contain assignments');
    });
  });

  describe('wrapLiteralPrimitive', () => {
    it('should wrap a literal primitive', () => {
      expect(unparse(validate(createParser().wrapLiteralPrimitive('foo', null)))).toEqual('"foo"');
    });
  });

  describe('error recovery', () => {
    function recover(text: string, expected?: string) {
      const expr = validate(parseAction(text));
      expect(unparse(expr)).toEqual(expected || text);
    }
    it('should be able to recover from an extra paren', () => recover('((a)))', 'a'));
    it('should be able to recover from an extra bracket', () => recover('[[a]]]', '[[a]]'));
    it('should be able to recover from a missing )', () => recover('(a;b', 'a; b;'));
    it('should be able to recover from a missing ]', () => recover('[a,b', '[a, b]'));
    it('should be able to recover from a missing selector', () => recover('a.'));
    it('should be able to recover from a missing selector in a array literal',
       () => recover('[[a.], b, c]'));
  });

  describe('offsets', () => {
    it('should retain the offsets of an interpolation', () => {
      const interpolations = splitInterpolation('{{a}}  {{b}}  {{c}}') !;
      expect(interpolations.offsets).toEqual([2, 9, 16]);
    });

    it('should retain the offsets into the expression AST of interpolations', () => {
      const source = parseInterpolation('{{a}}  {{b}}  {{c}}') !;
      const interpolation = source.ast as Interpolation;
      expect(interpolation.expressions.map(e => e.span.start)).toEqual([2, 9, 16]);
    });
  });
});

function createParser() {
  return new Parser(new Lexer());
}

function parseAction(text: string, location: any = null): ASTWithSource {
  return createParser().parseAction(text, location);
}

function parseBinding(text: string, location: any = null): ASTWithSource {
  return createParser().parseBinding(text, location);
}

function parseTemplateBindingsResult(
    key: string, value: string, location: any = null): TemplateBindingParseResult {
  return createParser().parseTemplateBindings(key, value, location);
}
function parseTemplateBindings(
    key: string, value: string, location: any = null): TemplateBinding[] {
  return parseTemplateBindingsResult(key, value, location).templateBindings;
}

function parseInterpolation(text: string, location: any = null): ASTWithSource|null {
  return createParser().parseInterpolation(text, location);
}

function splitInterpolation(text: string, location: any = null): SplitInterpolation|null {
  return createParser().splitInterpolation(text, location);
}

function parseSimpleBinding(text: string, location: any = null): ASTWithSource {
  return createParser().parseSimpleBinding(text, location);
}

function checkInterpolation(exp: string, expected?: string) {
  const ast = parseInterpolation(exp) !;
  if (expected == null) expected = exp;
  expect(unparse(ast)).toEqual(expected);
  validate(ast);
}

function checkBinding(exp: string, expected?: string) {
  const ast = parseBinding(exp);
  if (expected == null) expected = exp;
  expect(unparse(ast)).toEqual(expected);
  validate(ast);
}

function checkAction(exp: string, expected?: string) {
  const ast = parseAction(exp);
  if (expected == null) expected = exp;
  expect(unparse(ast)).toEqual(expected);
  validate(ast);
}

function expectError(ast: {errors: ParserError[]}, message: string) {
  for (const error of ast.errors) {
    if (error.message.indexOf(message) >= 0) {
      return;
    }
  }
  const errMsgs = ast.errors.map(err => err.message).join('\n');
  throw Error(
      `Expected an error containing "${message}" to be reported, but got the errors:\n` + errMsgs);
}

function expectActionError(text: string, message: string) {
  expectError(validate(parseAction(text)), message);
}

function expectBindingError(text: string, message: string) {
  expectError(validate(parseBinding(text)), message);
}