parser-transform/test/json.js

Streaming+Async lexer and parser

// Generated by CoffeeScript 2.3.2
(function() {
  // A starter JSON lexer
  var LongReadable, Stream, Tee, asyncjson_parser, expect, fs, json_lexer, json_parser;

  ({expect} = require('chai'));

  fs = require('fs');

  json_lexer = fs.readFileSync('test/json.l', 'utf8');

  json_parser = fs.readFileSync('test/json.y', 'utf8');

  asyncjson_parser = fs.readFileSync('test/json-async.y', 'utf8');

  Stream = require('stream');

  Tee = class Tee extends Stream.Transform {
    constructor(options = {}) {
      options.objectMode = true;
      super(options);
    }

    _transform(chunk, encoding, next) {
      console.log(chunk);
      this.push(chunk);
      next();
    }

  };

  LongReadable = class LongReadable extends Stream.Readable {
    constructor(options) {
      super(options);
      this.count = 0;
    }

    _read(size) {
      switch (this.count++) {
        case 0:
          this.push('[');
          break;
        case 21:
          this.push('4');
          break;
        case 22:
          this.push(']');
          break;
        case 23:
          setTimeout((() => {
            return this.push(null);
          }), 60);
          break;
        default:
          setTimeout((() => {
            return this.push('"yes",');
          }), 50);
      }
    }

  };

  describe('The module', function() {
    var Grammar, LexerParser, LexerTransform, ParserTransform, dfas, grammar, grammar2;
    ({LexerParser, LexerTransform, Grammar, ParserTransform} = require('..'));
    dfas = null;
    grammar = null;
    grammar2 = null;
    it('should build a lexer', function() {
      return dfas = LexerParser.parse(json_lexer);
    });
    it('should build a grammar', function() {
      return grammar = Grammar.fromString(json_parser, {
        mode: 'LALR1'
      }, 'bnf');
    });
    it('should build another grammar', function() {
      return grammar2 = Grammar.fromString(asyncjson_parser, {
        mode: 'LALR1'
      }, 'bnf');
    });
    return it('should parse two concurrent streams', function(done) {
      var counted, expected_rows, r, s, streamLexer, streamLexer2, streamLexer3, streamParser, streamParser2, streamParser3, w;
      // Test three concurrent streams

      // A stream is read from `package.json`
      s = fs.createReadStream('./package.json', 'utf8');
      s.setEncoding('utf8');
      streamLexer = new LexerTransform(dfas);
      streamParser = new ParserTransform(grammar);
      // The "background" stream is generated by code.
      w = new LongReadable;
      w.setEncoding('utf8');
      streamLexer2 = new LexerTransform(dfas);
      streamParser2 = new ParserTransform(grammar);
      // A third stream is read from `rows.json`
      r = fs.createReadStream('./test/rows.json', 'utf8');
      r.setEncoding('utf8');
      streamLexer3 = new LexerTransform(dfas);
      streamParser3 = new ParserTransform(grammar2);
      // All three streams are expected to complete.
      counted = 3;
      s.pipe(streamLexer).pipe(streamParser).on('data', function(data) {
        expect(data).to.have.property('name', 'parser-transform');
        expect(data).to.have.property('scripts').with.property('test');
        if (--counted === 0) {
          return done();
        }
      });
      // .pipe new Tee # use this to see chunks generated by the lexer
      // .pipe new Tee # use this to see chunks generated by the parser
      w.pipe(streamLexer2).pipe(streamParser2).on('data', function(data) {
        expect(data).to.have.length(21);
        expect(data).to.have.property(0, 'yes');
        expect(data).to.have.property(1, 'yes');
        expect(data).to.have.property(20, 4);
        if (--counted === 0) {
          return done();
        }
      });
      expected_rows = 3;
      r.pipe(streamLexer3).pipe(streamParser3).on('data', function(data) {
        expect(data).to.have.property('prefix').with.length(2);
        expect(data).to.have.property('prefix').with.property(0, 'rows');
        expect(data).to.have.property('value').with.property('_id');
        if (--expected_rows !== 0) {
          return;
        }
        if (--counted === 0) {
          return done();
        }
      });
    });
  });

}).call(this);