如何使用 JavaScript 从对象数组中删除对象？

Question

I have an array of objects where some objects are undefined and I want to know how to remove them i got it how many of them but don't know how to remove them from an array of objects. i know this method to use but i want some more standard way to do it

    const data = [
        {
            roleDoc:{
                name:"A"
            }
        },
        { roleDoc: undefined }
        ,{
            roleDoc:{
                name:"c"
            }
        },{
            roleDoc:{
                name:"c"
            }
        },
        { roleDoc: undefined },
        ,{
            roleDoc:{
                name:"c"
            }
        }

    ]
 const xy = []
data.forEach(item => {
    if(item.roleDoc !== undefined){
       xy.push(item) 
    }
    else{
        console.log('hello')
    }
})
console.log(xy)

expected output is

const data = [
  {
    roleDoc: {
      name: "A"
    }
  },

  ,
  {
    roleDoc: {
      name: "c"
    }
  },
  {
    roleDoc: {
      name: "c"
    }
  },

  ,
  {
    roleDoc: {
      name: "c"
    }
  }
];

Answer 1

You can use .filter() to remove undefined ones.

Try the following:

 const data = [{ roleDoc:{ name:"A" } }, { roleDoc: undefined } ,{ roleDoc:{ name:"c"}},{roleDoc:{name:"c"} }, { roleDoc: undefined },{ roleDoc:{name:"c"}}]; const result = data.filter(e => e.roleDoc); console.log(result);

I hope this helps!

Answer 2

You could do with Array#filter and !! only matched valid

 const data = [ { roleDoc:{ name:"A" } }, { roleDoc: undefined } ,{ roleDoc:{ name:"c" } },{ roleDoc:{ name:"c" } }, { roleDoc: undefined },{ roleDoc:{ name:"c" } }]; let res = data.filter(a=> !!a.roleDoc); console.log(res)

Answer 3

You could use a function programming approach using the Array.filter function:

const data = [
    {
        roleDoc: {
            name: "A"
        }
    },
    { 
        roleDoc: undefined 
    },
    {
        roleDoc: {
            name: "c"
        }
    },
    {
        roleDoc: {
            name: "c"
        }
    },
    { 
        roleDoc: undefined
    },
    {
        roleDoc: {
            name: "c"
        }
    }
];

const arrayWithoutUndefineds = data.filter(el => typeof el.roleDoc !== 'undefined');

console.log(arrayWithoutUndefineds);

Note that the expression used could be simplied. However, so it it clear what it happening I will leave it there.