> ## Documentation Index
> Fetch the complete documentation index at: https://hellocsv.mintlify.app/llms.txt
> Use this file to discover all available pages before exploring further.

# CSV Importer State Builder

This section describes the state builder object of the importer.

## constructor

**Parameters:** `importerDefinition: Pick<
  ImporterDefinition,   | 'sheets'   | 'customFileLoaders'   | 'customSuggestedMapper'   | 'onDataColumnsMapped'>`

**Description:**\
Defines the importer configuration. Checkout the [Importer Props](/v0.3.7/api-reference/importer-props) section for more information.

***

# Methods

The order of the methods might be important. Please follow the order defined below. You don't need to run all the methods though.

## uploadFile

**Parameters:** `file: File`

**Required to call next steps:** Yes

**Description:**\
Keep in mind that this is asynchronous function. Make sure to await the result of it.

The function simulates the upload of a file. It will parse the file and build the suggested mappings.

## setEnterDataManually

**Parameters:** `amountOfEmptyRowsToAdd?: number`

**Required to call next steps:** No

**Description:**\
This method will add empty rows to the current sheet and switch the mode to preview - this means that it will skip
the mapping step and ignore uploaded file.

## setMappings

**Parameters:** `mappings: ColumnMapping[]`

**Required to call next steps:** No

**Description:**\
This method will set the mappings for the current sheet.

## confirmMappings

**Parameters:** `mappings: ColumnMapping[]`

**Required to call next steps:** Yes

**Description:**

Remember that this is asynchronous function. Make sure to await the result of it.

Confirm the mappings for the current sheet. This will switch the mode to preview.

## getState

**Parameters:** `none`

**Description:**\
Returns the built state. This should be the last method you call.
Function is async, so you need to await it's results.

# Example

```tsx theme={null}
import { useEffect, useState } from 'preact/hooks';
import Importer, {
  CsvImporterStateBuilder,
  ImporterDefinition,
  ImporterState,
} from 'hello-csv/preact';
import Content from '../Content';
import DocumentContainer from '../DocumentContainer';
import example1 from '../../assets/datasets/example-1.csv?url';

export default function EmployeeImporter() {
  const [ready, setReady] = useState(false);
  const [initialState, setInitialState] = useState<ImporterState | undefined>(
    undefined
  );

  const onComplete = async (
    data: ImporterState,
    onProgress: (progress: number) => void
  ) => {
    await new Promise((resolve) => setTimeout(resolve, 200));
    onProgress(20);
    await new Promise((resolve) => setTimeout(resolve, 200));
    onProgress(50);
    await new Promise((resolve) => setTimeout(resolve, 200));
    onProgress(100);
    console.log(data);
    setReady(true);
  };

  const importerDefinition: ImporterDefinition = {
    allowManualDataEntry: true,
    maxFileSizeInBytes: 10 * 1024 * 1024, // 10MB
    sheets: [
      {
        id: 'employees',
        label: 'Employees',
        columns: [
          {
            label: 'Employee ID',
            id: 'employee.id',
            type: 'number',
            validators: [
              { validate: 'required' },
              {
                validate: 'unique',
                error: 'This employee ID is not unique',
              },
              {
                validate: 'is_integer',
                error: 'This value must be a number',
              },
            ],
          },
          {
            label: 'Email',
            id: 'email',
            type: 'string',
            validators: [
              { validate: 'required' },
              { validate: 'unique', error: 'This email is not unique' },
              {
                validate: 'email',
                error: 'This email is not valid',
              },
            ],
          },
          {
            label: 'Phone Number',
            id: 'phone_number',
            type: 'string',
            validators: [
              { validate: 'required' },
              { validate: 'phone_number' },
            ],
          },
          {
            label: 'Address',
            id: 'address',
            type: 'string',
            validators: [{ validate: 'required' }],
          },
          { label: 'City', id: 'city', type: 'string' },
          {
            label: 'State',
            id: 'state',
            type: 'string',
            transformers: [{ transformer: 'state_code' }],
          },
          {
            label: 'Zip Code',
            id: 'zip_code',
            type: 'string',
            validators: [{ validate: 'required' }, { validate: 'postal_code' }],
          },
          {
            label: 'Full address',
            id: 'full_address',
            type: 'calculated',
            typeArguments: {
              getValue: (row) =>
                `${row.address}, ${row.city}, ${row.state} ${row.zip_code}`,
            },
          },
        ],
      },
    ],
    onDataColumnsMapped: (dataColumns) => {
      return dataColumns;
    },
    onComplete,
    preventUploadOnValidationErrors: true,
    persistenceConfig: {
      enabled: true,
    },
  };

  useEffect(() => {
    const run = async () => {
      const stateBuilder = new CsvImporterStateBuilder(importerDefinition);

      const csvContent = `employee_id,email,phone_number,address,city,state,zip_code
  1234567,john.smith@company.com,555-123-4567,123 Main Street,Seattle,WA,98101
  2345678,emma.wilson@company.com,555-234-5678,456 Oak Avenue,Portland,OR,97201`;

      const file = new File([csvContent], 'example-1.csv', {
        type: 'text/csv',
      });

      await stateBuilder.uploadFile(file);
      await stateBuilder.confirmMappings();

      setInitialState(await stateBuilder.getState());
    };

    run();
  }, []);

  if (initialState == null) {
    return <div>Loading...</div>;
  }

  return (
    <>
      <div className="mt-4 flex max-h-[800px] rounded-lg border border-gray-200 bg-white px-2 py-6 sm:px-8">
        <Importer {...importerDefinition} initialState={initialState} />
      </div>
      {ready && (
        <div>
          <h4>Check the console for the output!</h4>
        </div>
      )}
    </>
  );
}
```