function deriveMappingAndCustomTypeInfo()

in src/utils/configUtils.js [485:516]

• 32 lines of code
• 4 McCabe index (conditional complexity)

function deriveMappingAndCustomTypeInfo(
  firstLine: Array<?string>,
): {
  mapping: {[string]: string},
  customTypeInfo: {[string]: {baseType: 'text' | 'number'}}
} {
  const mapping = {};
  const customTypeInfo = {};
  firstLine.forEach((header, column) => {
    if (header == null) {
      throw new Error('Invalid header for preprocessed data.');
    }
    if (isCustomData(header)) {
      const indexOfColon = header.lastIndexOf(':');
      if (indexOfColon < 0) {
        throw new Error(
          `Custom data field '${header}' does not have a type, please use `
          + `either '${header}:text' or '${header}:number'.`,
        );
      }
      const customDataField = header.substring(0, indexOfColon);
      const typeField = header.substring(indexOfColon + 1);
      const customDataKey = customDataField
        .substring(customDataField.indexOf('.') + 1);
      mapping[String(column)] = customDataField;
      customTypeInfo[customDataKey] = {baseType: typeField};
    } else {
      mapping[String(column)] = header;
    }
  });
  return {mapping, customTypeInfo};
}