如何驗證使用 yup 檢查字符串最小長度、最大長度並允許為空

Question

firstName: yup
    .string()
    .test(
        'len',
        'can be empty or with string at least 2 characters and not more than 10',
        (val) => val != undefined && (val.length == 0 || (val.length >= 2 && val.length <= 10) )
    )

在這種情況下，長度 min 2 和 max 10 有效，但是當為空時標記為錯誤我嘗試使用val.length == 0

Answer 1

通過單獨的未定義檢查修復

  firstName: yup
            .string()
            .test(
                'len',
                'can be empty or with string at least 2 characters and not more than 10',
                (val) => {
                    if (val == undefined) {
                        return true;
                    }
                    return  ((val.length == 0 || (val.length >= 2 && val.length <= 10)))
                }
            ),

Answer 2

你好你可以這樣做

 const yup = require("yup"); const firstName = ""; const schema = yup.string().test( "len", "can be empty or with string at least 2 characters and not more than 10", (val) => { if (val === undefined) { return true; } return val.length === 0 || (val.length >= 2 && val.length <= 10); } ); schema.validate(firstName).then((response) => console.log(response)).catch((err) => console.log(err));