vant/src/field/utils.ts

import type { FieldRule } from './types';

function isEmptyValue(value: unknown) {
  if (Array.isArray(value)) {
    return !value.length;
  }
  if (value === 0) {
    return false;
  }
  return !value;
}

export function runSyncRule(value: unknown, rule: FieldRule) {
  if (rule.required && isEmptyValue(value)) {
    return false;
  }
  if (rule.pattern && !rule.pattern.test(String(value))) {
    return false;
  }
  return true;
}