1.7.0

Bug fixes

• (Web only) Fixed an issue where streaming large datasets could provide corrupted results. See #333 (PR) for more details.

New features

• Added JSONEachRowWithProgress format support, ProgressRow interface, and isProgressRow type guard. See this Node.js example for more details. It should work similarly with the Web version.

• (Experimental) Exposed the parseColumnType function that takes a string representation of a ClickHouse type (e.g., FixedString(16), Nullable(Int32), etc.) and returns an AST-like object that represents the type. For example:

  for (const type of [
    'Int32',
    'Array(Nullable(String))',
    `Map(Int32, DateTime64(9, 'UTC'))`,
  ]) {
    console.log(`##### Source ClickHouse type: ${type}`)
    console.log(parseColumnType(type))
  }

  The above code will output:

  ##### Source ClickHouse type: Int32
  { type: 'Simple', columnType: 'Int32', sourceType: 'Int32' }
  ##### Source ClickHouse type: Array(Nullable(String))
  {
    type: 'Array',
    value: {
      type: 'Nullable',
      sourceType: 'Nullable(String)',
      value: { type: 'Simple', columnType: 'String', sourceType: 'String' }
    },
    dimensions: 1,
    sourceType: 'Array(Nullable(String))'
  }
  ##### Source ClickHouse type: Map(Int32, DateTime64(9, 'UTC'))
  {
    type: 'Map',
    key: { type: 'Simple', columnType: 'Int32', sourceType: 'Int32' },
    value: {
      type: 'DateTime64',
      timezone: 'UTC',
      precision: 9,
      sourceType: "DateTime64(9, 'UTC')"
    },
    sourceType: "Map(Int32, DateTime64(9, 'UTC'))"
  }
  

  While the original intention was to use this function internally for Native/RowBinaryWithNamesAndTypes data formats headers parsing, it can be useful for other purposes as well (e.g., interfaces generation, or custom JSON serializers).

  NB: currently unsupported source types to parse:

  • Geo
  • (Simple)AggregateFunction
  • Nested
  • Old/new experimental JSON
  • Dynamic
  • Variant