Question

我有以下对象：

   let params = {
            limit: limit,
            offset: 15,
            status: "completed",
            product_id: this.route.snapshot.queryParams.product_id,
        };

以上对象包含用于过滤我的数据源的参数。

this.route.snapshot.queryParams.product_id是一个查询/获取参数

？product_id = 123

但是，如果不存在此值，则未定义。因此，如果此值未定义，我不想将product_id成员添加到参数对象。

如果未定义，则对象应类似于：

   let params = {
            limit: limit,
            offset: 15,
            status: "completed",
        };

Answer 1

仅在未定义product_id时添加

let params = {
        limit: limit,
        offset: 15,
        status: "completed",
    };

if(this.route.snapshot.queryParams.product_id)
   params['product_id'] = this.route.snapshot.queryParams.product_id;

Answer 2

内联解决方案：

[[TP  FP][FN  TN]]

或更短：

let params = {
  limit: limit,
  offset: 15,
  status: "completed",
  ...this.route.snapshot.queryParams.product_id && {product_id: this.route.snapshot.queryParams.product_id},
};

Answer 3

您也可以尝试：

let param = { product_id:this.route.snapshot.queryParams.product_id }
params = this.route.snapshot.queryParams.product_id ? {...params, ...param} : params ;

Answer 4

我认为您不能内联执行此操作，但是

let params:object;
if ( this.route.snapshot.queryParams.product_id){
    params = {
            limit: limit,
            offset: 15,
            status: "completed",
            product_id: this.route.snapshot.queryParams.product_id,
        };
        }
else{
    params = {
            limit: limit,
            offset: 15,
            status: "completed",
        };  
}

将完成任务。

Answer 5

您可以通过以下方法进行对象分解

var param = {
            limit: 5,
            offset: 15,
            status: "completed",
            product_id: undefined,
        };
var { product_id, ...rest } = param

param = { ...(product_id && { product_id }), ...rest }

Answer 6

过去，当我这样做时，我将使用类似于以下示例的内容。我觉得可能有一种更好的方法，但是我还没有找到。

const removeUndefinedValues = objectIn => Object.keys(objectIn)
  .reduce((prev, curr) => {
    return objectIn[curr] !== undefined ?
      {
        ...prev,
        [curr]: objectIn[curr]
      } : prev
  }, {})

let paramsOne = {
    limit: 0,
    offset: 15,
    status: "completed",
    product_id: undefined,
}

let paramsTwo = {
    limit: 0,
    offset: 15,
    status: "completed",
    product_id: "A value",
}

console.dir(removeUndefinedValues(paramsOne))
console.dir(removeUndefinedValues(paramsTwo))

Answer 7

我个人认为您应该让product_id处于未定义状态，然后检查它是否在后面，但是您可以执行以下操作：

let params = {
  limit: limit,
  offset: 15,
  status: "completed",
};

if(this.route.snapshot.queryParams.product_id) {
  params['product_id'] = this.route.snapshot.queryParams.product_id;
}

Answer 8

您对以下内容的看法

const constantParams= {
   limit: limit,
   offset: 15,
   status: "completed",
}
let yourDynamicObject = this.route.snapshot.queryParams.product_id 
? {...constantParams, product_id: this.route.snapshot.queryParams.product_id}
: this.paramsWichAreAlwaysThere

Answer 9

有多种方法可以实现这一目标。我会指出其中两个。您可以简单地使用if语句添加product_id字段

let product_id = this.route.snapshot.queryParams.product_id;
if(product_id) {
    params.product_id = product_id;
}

或

您可以使用拆分运算符

let product_id = this.route.snapshot.queryParams.product_id;
let params = {
    limit: limit,
    offset: 15,
    status: "completed",
    ...product_id ? {product_id} : {},
};

Answer 10

这应该可以完成工作：

let params = {
        limit: limit,
        offset: 15,
        status: "completed",
    };

if (this.route.snapshot.queryParams.product_id) {
   params["product_id"] = this.route.snapshot.queryParams.product_id
}

Answer 11

尝试一下

  const product_id = this.route.snapshot.queryParams.product_id;

  let params = Object.assign({
            limit: limit,
            offset: 15,
            status: "completed"
        }, product_id ? {product_id} : {});

Answer 12

如何构造具有3个成员并随后根据条件附加的params对象。

let params = {
  limit: limit,
  offset: 15,
  status: "completed",
};
var value = this.route.snapshot.queryParams.product_id;
if (value) {
  params.product_id = value
}

仅在属性未定义的情况下才将属性添加到对象

12 个答案: