parser-test.js

// @flow strict

import { inspect as nodeInspect } from 'util';

import { expect } from 'chai';
import { describe, it } from 'mocha';

import dedent from '../../__testUtils__/dedent';

import inspect from '../../jsutils/inspect';

import { Kind } from '../kinds';
import { Source } from '../source';
import { TokenKind } from '../tokenKind';
import { parse, parseValue, parseType } from '../parser';

import { kitchenSinkQuery } from '../../__fixtures__/index';

import toJSONDeep from './toJSONDeep';

function expectSyntaxError(text) {
  return expect(() => parse(text)).to.throw();
}

describe('Parser', () => {
  it('asserts that a source to parse was provided', () => {
    // $FlowExpectedError
    expect(() => parse()).to.throw('Must provide Source. Received: undefined.');
  });

  it('asserts that an invalid source to parse was provided', () => {
    // $FlowExpectedError
    expect(() => parse({})).to.throw('Must provide Source. Received: {}.');
  });

  it('parse provides useful errors', () => {
    let caughtError;
    try {
      parse('{');
    } catch (error) {
      caughtError = error;
    }

    expect(caughtError).to.deep.contain({
      message: 'Syntax Error: Expected Name, found <EOF>.',
      positions: [1],
      locations: [{ line: 1, column: 2 }],
    });

    expect(String(caughtError) + '\n').to.equal(dedent`
      Syntax Error: Expected Name, found <EOF>.

      GraphQL request:1:2
      1 | {
        |  ^
    `);

    expectSyntaxError(`
      { ...MissingOn }
      fragment MissingOn Type
    `).to.deep.include({
      message: 'Syntax Error: Expected "on", found Name "Type".',
      locations: [{ line: 3, column: 26 }],
    });

    expectSyntaxError('{ field: {} }').to.deep.include({
      message: 'Syntax Error: Expected Name, found "{".',
      locations: [{ line: 1, column: 10 }],
    });

    expectSyntaxError('notAnOperation Foo { field }').to.deep.include({
      message: 'Syntax Error: Unexpected Name "notAnOperation".',
      locations: [{ line: 1, column: 1 }],
    });

    expectSyntaxError('...').to.deep.include({
      message: 'Syntax Error: Unexpected "...".',
      locations: [{ line: 1, column: 1 }],
    });

    expectSyntaxError('{ ""').to.deep.include({
      message: 'Syntax Error: Expected Name, found String "".',
      locations: [{ line: 1, column: 3 }],
    });
  });

  it('parse provides useful error when using source', () => {
    let caughtError;
    try {
      parse(new Source('query', 'MyQuery.graphql'));
    } catch (error) {
      caughtError = error;
    }
    expect(String(caughtError) + '\n').to.equal(dedent`
      Syntax Error: Expected "{", found <EOF>.

      MyQuery.graphql:1:6
      1 | query
        |      ^
    `);
  });

  it('parses variable inline values', () => {
    expect(() =>
      parse('{ field(complex: { a: { b: [ $var ] } }) }'),
    ).to.not.throw();
  });

  it('parses constant default values', () => {
    expectSyntaxError(
      'query Foo($x: Complex = { a: { b: [ $var ] } }) { field }',
    ).to.deep.equal({
      message: 'Syntax Error: Unexpected "$".',
      locations: [{ line: 1, column: 37 }],
    });
  });

  it('parses variable definition directives', () => {
    expect(() =>
      parse('query Foo($x: Boolean = false @bar) { field }'),
    ).to.not.throw();
  });

  it('does not accept fragments named "on"', () => {
    expectSyntaxError('fragment on on on { on }').to.deep.equal({
      message: 'Syntax Error: Unexpected Name "on".',
      locations: [{ line: 1, column: 10 }],
    });
  });

  it('does not accept fragments spread of "on"', () => {
    expectSyntaxError('{ ...on }').to.deep.equal({
      message: 'Syntax Error: Expected Name, found "}".',
      locations: [{ line: 1, column: 9 }],
    });
  });

  it('parses multi-byte characters', () => {
    // Note: \u0A0A could be naively interpreted as two line-feed chars.
    const ast = parse(`
      # This comment has a \u0A0A multi-byte character.
      { field(arg: "Has a \u0A0A multi-byte character.") }
    `);

    expect(ast).to.have.nested.property(
      'definitions[0].selectionSet.selections[0].arguments[0].value.value',
      'Has a \u0A0A multi-byte character.',
    );
  });

  it('parses kitchen sink', () => {
    expect(() => parse(kitchenSinkQuery)).to.not.throw();
  });

  it('allows non-keywords anywhere a Name is allowed', () => {
    const nonKeywords = [
      'on',
      'fragment',
      'query',
      'mutation',
      'subscription',
      'true',
      'false',
    ];
    for (const keyword of nonKeywords) {
      // You can't define or reference a fragment named `on`.
      const fragmentName = keyword !== 'on' ? keyword : 'a';
      const document = `
        query ${keyword} {
          ... ${fragmentName}
          ... on ${keyword} { field }
        }
        fragment ${fragmentName} on Type {
          ${keyword}(${keyword}: $${keyword})
            @${keyword}(${keyword}: ${keyword})
        }
      `;

      expect(() => parse(document)).to.not.throw();
    }
  });

  it('parses anonymous mutation operations', () => {
    expect(() =>
      parse(`
      mutation {
        mutationField
      }
    `),
    ).to.not.throw();
  });

  it('parses anonymous subscription operations', () => {
    expect(() =>
      parse(`
      subscription {
        subscriptionField
      }
    `),
    ).to.not.throw();
  });

  it('parses named mutation operations', () => {
    expect(() =>
      parse(`
      mutation Foo {
        mutationField
      }
    `),
    ).to.not.throw();
  });

  it('parses named subscription operations', () => {
    expect(() =>
      parse(`
      subscription Foo {
        subscriptionField
      }
    `),
    ).to.not.throw();
  });

  it('creates ast', () => {
    const result = parse(dedent`
      {
        node(id: 4) {
          id,
          name
        }
      }
    `);

    expect(toJSONDeep(result)).to.deep.equal({
      kind: Kind.DOCUMENT,
      loc: { start: 0, end: 41 },
      definitions: [
        {
          kind: Kind.OPERATION_DEFINITION,
          loc: { start: 0, end: 40 },
          operation: 'query',
          name: undefined,
          variableDefinitions: [],
          directives: [],
          selectionSet: {
            kind: Kind.SELECTION_SET,
            loc: { start: 0, end: 40 },
            selections: [
              {
                kind: Kind.FIELD,
                loc: { start: 4, end: 38 },
                alias: undefined,
                name: {
                  kind: Kind.NAME,
                  loc: { start: 4, end: 8 },
                  value: 'node',
                },
                arguments: [
                  {
                    kind: Kind.ARGUMENT,
                    name: {
                      kind: Kind.NAME,
                      loc: { start: 9, end: 11 },
                      value: 'id',
                    },
                    value: {
                      kind: Kind.INT,
                      loc: { start: 13, end: 14 },
                      value: '4',
                    },
                    loc: { start: 9, end: 14 },
                  },
                ],
                directives: [],
                selectionSet: {
                  kind: Kind.SELECTION_SET,
                  loc: { start: 16, end: 38 },
                  selections: [
                    {
                      kind: Kind.FIELD,
                      loc: { start: 22, end: 24 },
                      alias: undefined,
                      name: {
                        kind: Kind.NAME,
                        loc: { start: 22, end: 24 },
                        value: 'id',
                      },
                      arguments: [],
                      directives: [],
                      selectionSet: undefined,
                    },
                    {
                      kind: Kind.FIELD,
                      loc: { start: 30, end: 34 },
                      alias: undefined,
                      name: {
                        kind: Kind.NAME,
                        loc: { start: 30, end: 34 },
                        value: 'name',
                      },
                      arguments: [],
                      directives: [],
                      selectionSet: undefined,
                    },
                  ],
                },
              },
            ],
          },
        },
      ],
    });
  });

  it('creates ast from nameless query without variables', () => {
    const result = parse(dedent`
      query {
        node {
          id
        }
      }
    `);

    expect(toJSONDeep(result)).to.deep.equal({
      kind: Kind.DOCUMENT,
      loc: { start: 0, end: 30 },
      definitions: [
        {
          kind: Kind.OPERATION_DEFINITION,
          loc: { start: 0, end: 29 },
          operation: 'query',
          name: undefined,
          variableDefinitions: [],
          directives: [],
          selectionSet: {
            kind: Kind.SELECTION_SET,
            loc: { start: 6, end: 29 },
            selections: [
              {
                kind: Kind.FIELD,
                loc: { start: 10, end: 27 },
                alias: undefined,
                name: {
                  kind: Kind.NAME,
                  loc: { start: 10, end: 14 },
                  value: 'node',
                },
                arguments: [],
                directives: [],
                selectionSet: {
                  kind: Kind.SELECTION_SET,
                  loc: { start: 15, end: 27 },
                  selections: [
                    {
                      kind: Kind.FIELD,
                      loc: { start: 21, end: 23 },
                      alias: undefined,
                      name: {
                        kind: Kind.NAME,
                        loc: { start: 21, end: 23 },
                        value: 'id',
                      },
                      arguments: [],
                      directives: [],
                      selectionSet: undefined,
                    },
                  ],
                },
              },
            ],
          },
        },
      ],
    });
  });

  it('allows parsing without source location information', () => {
    const result = parse('{ id }', { noLocation: true });
    expect(result.loc).to.equal(undefined);
  });

  it('Experimental: allows parsing fragment defined variables', () => {
    const document = 'fragment a($v: Boolean = false) on t { f(v: $v) }';

    expect(() =>
      parse(document, { experimentalFragmentVariables: true }),
    ).to.not.throw();
    expect(() => parse(document)).to.throw('Syntax Error');
  });

  it('contains location information that only stringifies start/end', () => {
    const result = parse('{ id }');

    expect(JSON.stringify(result.loc)).to.equal('{"start":0,"end":6}');
    expect(nodeInspect(result.loc)).to.equal('{ start: 0, end: 6 }');
    expect(inspect(result.loc)).to.equal('{ start: 0, end: 6 }');
  });

  it('contains references to source', () => {
    const source = new Source('{ id }');
    const result = parse(source);

    expect(result).to.have.nested.property('loc.source', source);
  });

  it('contains references to start and end tokens', () => {
    const result = parse('{ id }');

    expect(result).to.have.nested.property(
      'loc.startToken.kind',
      TokenKind.SOF,
    );
    expect(result).to.have.nested.property('loc.endToken.kind', TokenKind.EOF);
  });

  describe('parseValue', () => {
    it('parses null value', () => {
      const result = parseValue('null');
      expect(toJSONDeep(result)).to.deep.equal({
        kind: Kind.NULL,
        loc: { start: 0, end: 4 },
      });
    });

    it('parses list values', () => {
      const result = parseValue('[123 "abc"]');
      expect(toJSONDeep(result)).to.deep.equal({
        kind: Kind.LIST,
        loc: { start: 0, end: 11 },
        values: [
          {
            kind: Kind.INT,
            loc: { start: 1, end: 4 },
            value: '123',
          },
          {
            kind: Kind.STRING,
            loc: { start: 5, end: 10 },
            value: 'abc',
            block: false,
          },
        ],
      });
    });

    it('parses block strings', () => {
      const result = parseValue('["""long""" "short"]');
      expect(toJSONDeep(result)).to.deep.equal({
        kind: Kind.LIST,
        loc: { start: 0, end: 20 },
        values: [
          {
            kind: Kind.STRING,
            loc: { start: 1, end: 11 },
            value: 'long',
            block: true,
          },
          {
            kind: Kind.STRING,
            loc: { start: 12, end: 19 },
            value: 'short',
            block: false,
          },
        ],
      });
    });
  });

  describe('parseType', () => {
    it('parses well known types', () => {
      const result = parseType('String');
      expect(toJSONDeep(result)).to.deep.equal({
        kind: Kind.NAMED_TYPE,
        loc: { start: 0, end: 6 },
        name: {
          kind: Kind.NAME,
          loc: { start: 0, end: 6 },
          value: 'String',
        },
      });
    });

    it('parses custom types', () => {
      const result = parseType('MyType');
      expect(toJSONDeep(result)).to.deep.equal({
        kind: Kind.NAMED_TYPE,
        loc: { start: 0, end: 6 },
        name: {
          kind: Kind.NAME,
          loc: { start: 0, end: 6 },
          value: 'MyType',
        },
      });
    });

    it('parses list types', () => {
      const result = parseType('[MyType]');
      expect(toJSONDeep(result)).to.deep.equal({
        kind: Kind.LIST_TYPE,
        loc: { start: 0, end: 8 },
        type: {
          kind: Kind.NAMED_TYPE,
          loc: { start: 1, end: 7 },
          name: {
            kind: Kind.NAME,
            loc: { start: 1, end: 7 },
            value: 'MyType',
          },
        },
      });
    });

    it('parses non-null types', () => {
      const result = parseType('MyType!');
      expect(toJSONDeep(result)).to.deep.equal({
        kind: Kind.NON_NULL_TYPE,
        loc: { start: 0, end: 7 },
        type: {
          kind: Kind.NAMED_TYPE,
          loc: { start: 0, end: 6 },
          name: {
            kind: Kind.NAME,
            loc: { start: 0, end: 6 },
            value: 'MyType',
          },
        },
      });
    });

    it('parses nested types', () => {
      const result = parseType('[MyType!]');
      expect(toJSONDeep(result)).to.deep.equal({
        kind: Kind.LIST_TYPE,
        loc: { start: 0, end: 9 },
        type: {
          kind: Kind.NON_NULL_TYPE,
          loc: { start: 1, end: 8 },
          type: {
            kind: Kind.NAMED_TYPE,
            loc: { start: 1, end: 7 },
            name: {
              kind: Kind.NAME,
              loc: { start: 1, end: 7 },
              value: 'MyType',
            },
          },
        },
      });
    });
  });
});