我正在尝试使用以下正则表达式验证字符串（电话号码）^+[0-9]{9，12}$
但是我得到了这个错误... .pattern should match format "regex" ...
我看过https://ajv.js.org等的文档。看看例子等等。我尝试了很多变化，但似乎不能找出我的代码有什么问题。
下面是我的代码：

const schema = {
    type: 'object',
    properties: {
        users: {
            type: 'array',
            items: {
                type: 'object',
                properties: {
                    userReference: { type: 'string' },
                    phone: {
                        type: 'string'
                        , pattern: "^\+[0-9]{9,12}$" // If I remove this line, the model is seen as valid (and no errors)
                    }
                }
            }
        }
    },
    required: ['users'],
    errorMessage: { _: "One or more of the fields in the 'legacy' data path are incorrect." }
};

const schemaSample = {
    "users": [
        {
            "phone": "+25512345678", // should be valid
            "userReference": "AAA"
        },
        {
            "phone": "+5255 abc 12345678", // should be invalid
            "userReference": "BBB"
        }
    ]
};

var ajv = Ajv();
ajv.addSchema(schema, 'schema');

var valid = ajv.validate('schema', schemaSample);
if (valid) {
    console.log('Model is valid!');
} else {
    console.log('Model is invalid!');
}

链接到JSFiddle：http://jsfiddle.net/xnw2b9zL/4/（打开控制台/调试器以查看完整错误）