javascript - 使用条件 : is a number? 减少方法 os 对象数组

Question

我有一个数组:

const products = [
    { product: 'banana', price: 3 },
    { product: 'mango', price: 6 },
    { product: 'potato', price: ' ' },
    { product: 'avocado', price: 8 },
    { product: 'coffee', price: 10 },
    { product: 'tea', price: '' },
  ]
  

我想总结所有价格。我尝试了什么:

const sum = products.reduce(function(acc, cur){
if (Number.isInteger(cur.price))
  return acc+cur.price

  }, 0)
 console.log(sum)

它返回未定义。我也试过没有条件，它返回一个字符串。我在哪里犯了错误？

Answer 1

如果条件不为true，则需要返回累加器。

const
    products = [{ product: 'banana', price: 3 }, { product: 'mango', price: 6 }, { product: 'potato', price: ' ' }, { product: 'avocado', price: 8 }, { product: 'coffee', price: 10  }, { product: 'tea', price: '' }],
    sum = products.reduce(function(acc, cur) {
        if (Number.isInteger(cur.price)) return acc + cur.price;
        else return acc;
    }, 0);
    
console.log(sum);

更短的方法有条件地添加值，最后只返回累加器。

const
    products = [{ product: 'banana', price: 3 }, { product: 'mango', price: 6 }, { product: 'potato', price: ' ' }, { product: 'avocado', price: 8 }, { product: 'coffee', price: 10  }, { product: 'tea', price: '' }],
    sum = products.reduce(function(acc, cur) {
        if (Number.isInteger(cur.price)) acc += cur.price;
        return acc;
    }, 0);
    
console.log(sum);