@form-create/vant/src/core/provider.js

Vant 版本（移动端）低代码表单 | FormCreate 是一个可以通过 JSON 生成具有动态渲染、数据收集、验证和提交功能的低代码表单生成组件。

import is from '@form-create/utils/lib/type';

const required = {
    name: 'required',
    load(inject, rule, api) {
        const val = parseVal(inject.getValue());
        let _title = undefined;
        if (val.required === false) {
            inject.clearProp();
            api.clearValidateState([rule.field]);
        } else {
            const validate = {
                required: true,
                validator(v) {
                    updateMessage();
                    return !is.empty(v);
                },
                trigger: ['onChange', 'onSubmit'],
                ...val,
            };
            const updateMessage = () => {
                const title = rule.__fc__.refRule.__$title?.value;
                if (_title === title) {
                    return;
                }
                _title = title;
                if (!val.message) {
                    validate.message = api.t('required', {title}) || (title + (api.getLocale() === 'en' ? ' is required' : '不能为空'));
                } else {
                    const match = val.message.match(/^\{\{\s*\$t\.(.+)\s*\}\}$/);
                    if (match) {
                        validate.message = api.t(match[1], {title});
                    }
                }
            }
            updateMessage();
            inject.getProp().validate = [validate];
        }
        api.sync(rule);
    },
    watch(...args) {
        required.load(...args);
    }
}

function parseVal(val) {
    if (is.Boolean(val)) {
        return {required: val}
    } else if (is.String(val)) {
        return {message: val};
    } else if (is.Undef(val)) {
        return {required: false};
    } else if (is.Function(val)) {
        return {validator: val};
    } else if (!is.Object(val)) {
        return {};
    } else {
        return val;
    }
}


export default required