function appendOperation()

in backend/new.js [603:636]
33 lines of code
18 McCabe index (conditional complexity)

function appendOperation(outCols, inCols, operation) {
  let inIndex = 0, lastGroup = -1, lastCardinality = 0
  for (let outCol of outCols) {
    while (inIndex < inCols.length && inCols[inIndex].columnId < outCol.columnId) inIndex++

    if (inIndex < inCols.length && inCols[inIndex].columnId === outCol.columnId) {
      const colValue = operation[inIndex]
      if (outCol.columnId % 8 === COLUMN_TYPE.GROUP_CARD) {
        lastGroup = outCol.columnId >> 4
        lastCardinality = colValue
        outCol.encoder.appendValue(colValue)
      } else if (outCol.columnId >> 4 === lastGroup) {
        if (!Array.isArray(colValue) || colValue.length !== lastCardinality) {
          throw new RangeError('bad group value')
        }
        for (let v of colValue) outCol.encoder.appendValue(v)
      } else if (outCol.columnId % 8 === COLUMN_TYPE.VALUE_RAW) {
        if (colValue) outCol.encoder.appendRawBytes(colValue)
      } else {
        outCol.encoder.appendValue(colValue)
      }
    } else if (outCol.columnId % 8 === COLUMN_TYPE.GROUP_CARD) {
      lastGroup = outCol.columnId >> 4
      lastCardinality = 0
      outCol.encoder.appendValue(0)
    } else if (outCol.columnId % 8 !== COLUMN_TYPE.VALUE_RAW) {
      const count = (outCol.columnId >> 4 === lastGroup) ? lastCardinality : 1
      let blankValue = null
      if (outCol.columnId % 8 === COLUMN_TYPE.BOOLEAN) blankValue = false
      if (outCol.columnId % 8 === COLUMN_TYPE.VALUE_LEN) blankValue = 0
      outCol.encoder.appendValue(blankValue, count)
    }
  }
}