inspannings-monitor/lib/forms/parse.ts

const TIME_VALUE_PATTERN = /^([01]\d|2[0-3]):[0-5]\d$/;
const EMAIL_VALUE_PATTERN = /^[^\s@]+@[^\s@]+\.[^\s@]+$/;
const INTEGER_VALUE_PATTERN = /^-?\d+$/;
const UUID_VALUE_PATTERN =
  /^[0-9a-f]{8}-[0-9a-f]{4}-[1-5][0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$/i;

export class FormDataValidationError extends Error {
  code: string;

  constructor(code: string) {
    super(code);
    this.code = code;
    this.name = "FormDataValidationError";
  }
}

function fail(code: string): never {
  throw new FormDataValidationError(code);
}

export function getOptionalString(formData: FormData, key: string): string | null {
  const value = formData.get(key);

  if (typeof value !== "string") {
    return null;
  }

  return value.trim();
}

export function getRequiredString(
  formData: FormData,
  key: string,
  errorCode: string,
): string {
  const value = formData.get(key);

  if (typeof value !== "string") {
    fail(errorCode);
  }

  const trimmedValue = value.trim();

  if (!trimmedValue) {
    fail(errorCode);
  }

  return trimmedValue;
}

export function getBooleanValue(
  formData: FormData,
  key: string,
  errorCode: string,
): boolean {
  const value = formData.get(key);

  if (value === "true") {
    return true;
  }

  if (value === "false") {
    return false;
  }

  fail(errorCode);
}

export function getEnumValue<const TValue extends string>(
  formData: FormData,
  key: string,
  allowedValues: readonly TValue[],
  errorCode: string,
): TValue {
  const value = getRequiredString(formData, key, errorCode);

  if (!allowedValues.includes(value as TValue)) {
    fail(errorCode);
  }

  return value as TValue;
}

export function getOptionalTimeValue(
  formData: FormData,
  key: string,
  errorCode: string,
): string | null {
  const value = getOptionalString(formData, key);

  if (!value) {
    return null;
  }

  if (!TIME_VALUE_PATTERN.test(value)) {
    fail(errorCode);
  }

  return value;
}

export function assertEmail(value: string, errorCode: string): string {
  if (!EMAIL_VALUE_PATTERN.test(value)) {
    fail(errorCode);
  }

  return value;
}

export function assertMinLength(
  value: string,
  minimumLength: number,
  errorCode: string,
): string {
  if (value.length < minimumLength) {
    fail(errorCode);
  }

  return value;
}

export function assertMaxLength(
  value: string,
  maximumLength: number,
  errorCode: string,
): string {
  if (value.length > maximumLength) {
    fail(errorCode);
  }

  return value;
}

export function getIntegerValue(
  formData: FormData,
  key: string,
  range: { min: number; max: number },
  errorCode: string,
): number {
  const value = getRequiredString(formData, key, errorCode);

  if (!INTEGER_VALUE_PATTERN.test(value)) {
    fail(errorCode);
  }

  const parsedValue = Number.parseInt(value, 10);

  if (
    Number.isNaN(parsedValue) ||
    parsedValue < range.min ||
    parsedValue > range.max
  ) {
    fail(errorCode);
  }

  return parsedValue;
}

export function getUuidValue(
  formData: FormData,
  key: string,
  errorCode: string,
): string {
  const value = getRequiredString(formData, key, errorCode);

  if (!UUID_VALUE_PATTERN.test(value)) {
    fail(errorCode);
  }

  return value;
}

export function getOptionalUuidValue(
  formData: FormData,
  key: string,
  errorCode: string,
): string | null {
  const value = getOptionalString(formData, key);

  if (!value) {
    return null;
  }

  if (!UUID_VALUE_PATTERN.test(value)) {
    fail(errorCode);
  }

  return value;
}