Question

分为两个功能：

public valJson(json, schemaFile: string) {
    return new Promise((resolve, reject) => {
        this.http.get(schemaFile)
            .toPromise()
            .then(fileContents => fileContents.json())
            .then((schema) => {
                let ajv = new Ajv({allErrors: true});
                ajv.validate(schema, json) ? 
                resolve() :
                reject(new Error("JSON does not conform to schema: " + ajv.errorsText()));
            }, err => reject(
                new Error("Unable to get schema file contents:" + err))
            );
    });
};

这个功能确实有3件事情，所以单元测试并不是很好。

获取文件内容
将它们解析为json
验证json

如何解决这些问题以使每个任务都可以测试？

尝试打破实际的验证部分并不顺利：

public valJson(json, schemaFile: string) {
    return new Promise((resolve, reject) => {
        this.http.get(schemaFile)
            .toPromise()
            .then(fileContents => fileContents.json())
            .then((schema) => {
                this.valJ(schema)
            }, err => reject(
                new Error("Unable to get schema file contents:" + err))
            );
    });
};

    valJ(schema, json) {
        let ajv = new Ajv({ allErrors: true });
        if ajv.validate(schema, json) 
            return resolve()
        reject(new Error("JSON does not conform to schema: " + ajv.errorsText()));
    }
}

更新 - 根据反馈，我试图停止使用匿名函数，然后我将尝试不创建新的承诺。我在这里：

public valJson(json, schemaFile: string) {
    return new Promise((resolve, reject) => {
    var getFilePromise = this.http.get(schemaFile)
            .toPromise();
    var parseToJsonPromise = getFilePromise
            .then(contents => this.toJson(contents));
    var validateJsonPromise = parseToJsonPromise.then(schema => this.valJ(schema, json, resolve, reject),
            err => reject(
                new Error("Unable to get schema file contents:" + err))
            );
    });
};

toJson(fileContents): any {
    return fileContents.json()
}

valJ(schema, json, resolve, reject): any {
    let ajv = new Ajv({ allErrors: true });
    ajv.validate(schema, json) ?
        resolve() :
        reject(new Error("JSON does not conform to schema: " + ajv.errorsText())
    );
}

Answer 1

一种可能的方法：

public valJson(json, schemaFile: string) {
  return this.fetchSchema(schemaFile)
    .then(res => this.parseSchema(res))
    .then(schema => this.validateWithSchema(json, schema));
}

fetchSchema(url) {
  return this.http.get(url).toPromise();
}

parseSchema(response) {
  return response.json();
}

validateWithSchema(json, schema) {
  let ajv = new Ajv({allErrors: true});
  if (!ajv.validate(schema, json)) {
    throw new Error("JSON does not conform to schema: " + ajv.errorsText())
  }
}

打破承诺链成单独的功能

1 个答案: