plugin-validate-string

Features

• Regular expression pattern matching
• Length validation (min, max, exact)
• Case type enforcement (lowercase, uppercase, titlecase)
• Whitespace trimming (leading, trailing)
• Custom transformation functions
• Configurable error messages
• Common regex patterns for email, phone, and URL validation
• Empty string handling

Installation

To install the plugin, use npm:

npm install @flatfile/plugin-validate-string

Example Usage

import { FlatfileListener } from '@flatfile/listener';
import { validateString } from '@flatfile/plugin-validate-string';

const listener = new FlatfileListener();

const stringConfig = {
  fields: ['name'],
  minLength: 2,
  maxLength: 50,
  caseType: 'titlecase',
  errorMessages: {
    length: 'Name must be between 2 and 50 characters',
    case: 'Name must be in Title Case',
  },
  
};

listener.use(validateString(stringConfig));

Pattern usage:

const config = {
  fields: ['email'],
  pattern: 'email' // Uses predefined email pattern
};

// Or with a custom pattern:
const customConfig = {
  fields: ['customField'],
  pattern: /^[A-Z]{3}-\d{2}$/ // Custom pattern for format like 'ABC-12'
};

Configuration

The validateString accepts a StringValidationConfig object with the following properties:

• fields: string[] - Fields to validate
• sheetSlug: string - Sheet slug to validate (defaults to '**' all sheets)
• pattern: RegExp - A regular expression pattern to match against
• pattern: keyof typeof commonRegexPatterns | RegExp - A regular expression pattern to match against. You can use one of the predefined patterns ('email', 'phone', 'url') or provide a custom RegExp. The predefined patterns are:
  • email: Validates email addresses
  • phone: Validates phone numbers (10-14 digits, optional '+' prefix)
  • url: Validates URLs (with or without protocol)
• minLength: number - Minimum length of the string
• maxLength: number - Maximum length of the string
• exactLength: number - Exact required length of the string
• caseType: 'lowercase' | 'uppercase' | 'titlecase' - Enforces specific case type
• trim: { leading?: boolean, trailing?: boolean } - Trims whitespace
• emptyStringAllowed: boolean - Whether empty strings are allowed
• errorMessages: Object with custom error messages for different validations

Behavior

The plugin processes each record in the Flatfile import, applying the configured validations to the specified fields. If a validation fails, an error is added to the record for that field. If a custom transformation is specified and all validations pass, the transformed value is set for the field.

The plugin uses the recordHook to process individual records, allowing for efficient and flexible validation and transformation of string fields during the import process.