lianjie_admin/app/Admin/bootstrap.php

<?php

use Dcat\Admin\Admin;
use Dcat\Admin\Grid;
use Dcat\Admin\Form;
use Dcat\Admin\Grid\Filter;
use Dcat\Admin\Show;
use Dcat\Admin\Form\Field;

/**
 * Dcat-admin - admin builder based on Laravel.
 * @author jqh <https://github.com/jqhph>
 *
 * Bootstraper for Admin.
 *
 * Here you can remove builtin form field:
 *
 * extend custom field:
 * Dcat\Admin\Form::extend('php', PHPEditor::class);
 * Dcat\Admin\Grid\Column::extend('php', PHPEditor::class);
 * Dcat\Admin\Grid\Filter::extend('php', PHPEditor::class);
 *
 * Or require js and css assets:
 * Admin::css('/packages/prettydocs/css/styles.css');
 * Admin::js('/packages/prettydocs/js/main.js');
 *
 */

 // 官方例子，验证字符长度
Field\Text::macro('len', function (int $length, ?string $error = null) {
    // 前端验证逻辑扩展
    Admin::script(
                <<<'JS'
Dcat.validator.extend('len', function ($el) {
    console.log($el.val().length , $el.attr('data-len'));
    return $el.val().length != $el.attr('data-len');
});
JS
        );

        // 同时添加后端验证逻辑，这个可以看需要
        $this->rules('size:'.$length);

        return $this->attribute([
            'data-len'       => $length,
            'data-len-error' => str_replace(
                [':attribute', ':len'],
                [$this->label, $length],
                $error ?: "只能输入:len个字符"
            ),
        ]);
});

/* 验证最多包含两位小数的浮点数，可不带小数 */
Field\Text::macro('floatTwo', function (int $bit = 2, ?string $error = null) {
    // 前端验证逻辑扩展
    Admin::script(
                <<<'JS'
Dcat.validator.extend('floatTwo', function ($el) {
    return !(/^(([1-9]{1}\d*)|(0{1}))(\.\d{0,2})?$/.test($el.val()));
});
JS
        );

        // 同时添加后端验证逻辑，这个可以看需要
        // $this->rules('size:'.$length);

        return $this->attribute([
            'data-floatTwo'       => '^(([1-9]{1}\d*)|(0{1}))(\.\d{0,2})?$',
            'data-floatTwo-error' => "只能输入数字（最多包含两位小数）"
        ]);
});

/* 验证-选择不同优惠类型时的优惠金额验证 */
Field\Text::macro('discount', function ( ?string $error = null) {
    // 前端验证逻辑扩展
    Admin::script(
                <<<'JS'
Dcat.validator.extend('discount', function ($el) {
    $discount_type = $('');
    return !(/^(([1-9]{1}\d*)|(0{1}))(\.\d{0,2})?$/.test($el.val()));
});
JS
        );

        // 同时添加后端验证逻辑，这个可以看需要
        // $this->rules('size:'.$length);

        return $this->attribute([
            'data-discount'       => '1',
            'data-discount-error' =>  "只能输入数字"
        ]);
});