Filtering undefined from array of objects in Javascript

Question

I am having trouble sorting out the undefined from the array of objects that was crated from local storage. Lets assume that this array of of objects is localStorage:

var arrObject = [{date: undefined, bus_name: Thomas #1};...] Assume this has 2 dates that had undefined.

I want to be able to filter out the date that has undefined and the bus_name that is within the date so for example, if I used filter for an array of objects before sorting them, then {date: undefined, bus_name: Thomas #1} will not be included in the array that will be sorted.

How would I accomplish this?

Thanks!

UPDATE: 3/5/20

How would I accomplish this if I have more than 2 columns, lets say I have at least 5, I want to filter and sort date as well as only output date and bus_name

var arrObject = [{date: undefined, bus_name: Thomas #1, bus_driver: Thomas, time_start: 9AM, time_end: 5PM};...]

Output: {date: ..., bus_name:...}; {...}

@danh So I made a function that would create points for that array, how would I implement that onto there. function getPointsTable(data, points) { for (let i in data) { let point = []; let cols = Object.keys(data[0]); for (let j of cols) { point.push(j === 'date' ? Number(new Date(data[i][j])) : data[i][j]); } points.push(point) } return points } — Mark A Avila
– Mark A Avila, Commented Mar 3, 2020 at 19:27
@MarkAAvila Just to make sure I understand the question, you need to filter out all objects where date: undefined so that the array will only contain objects that have a date? — Joshua Kleveter
– Joshua Kleveter, Commented Mar 3, 2020 at 19:33
@JoshuaKleveter yes, dont forget that it will filter out the date that's undefined and the bus_name that contains it for example '{date: undefined, bus_name: Thomas #1}' should not be in the sorted array — Mark A Avila
– Mark A Avila, Commented Mar 3, 2020 at 19:36

AmitNayek · Accepted Answer · 2020-03-03 20:05:35Z

2

i think you should provide filter with condation field (one is date, another is bus_name )

anyway i want clear it out that :--

 i) arrObject.filter(e => e.date)  // with this all {date: undefined } contain object will be filter and get data which have actual date value 

 ii) arrObject.filter(e => e.date === undefined) // give filter result with all date undefined  
iii) arrObject.filter(e => e.date === undefined && e.bus_name ) or arrObject.filter(e => e.date && e.bus_name)

which one of the result you are expecting

answered Mar 3, 2020 at 20:05

AmitNayek

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2 Comments

Mark A Avila Over a year ago

The goal is for filter to filter out the date thats undefined or empty along with bus_name, since they are within the same array so Im assuming that the third option is the correct one.

AmitNayek Over a year ago

i think your sort portion you achieve by this arrObject1.filter((d) =>{ return d.date}).sort((a,b)=>new Date(b.date) - new Date(a.date))

Mechanic · Accepted Answer · 2020-03-03 20:51:27Z

1

You can use this method:

const arrObject = [
{date: undefined, bus_name: 'Thomas #1'},
{date: '2012-02-11', bus_name: 'Thomas #2'},
{date: '2012-02-02', bus_name: 'Thomas #3'},
{date: '2012-02-04', bus_name: 'Thomas #4'},
{date: undefined, bus_name: 'Thomas #5'},
{date: '2012-02-03', bus_name: 'Thomas #6'},
{date: '2012-02-03', bus_name: 'Thomas #7'},
]
function formatTheDate (str){
  //your format here
  let FormatedDate = "new Date format" + str 
  return FormatedDate
}

let newArray = arrObject.filter( obj => {
  obj.formattedDate = formatTheDate(obj.date)
  //behave same as obj.date != undefined
  return obj.date
}).sort((a,b)=>{
  return Date.parse(a.date) - Date.parse(b.date)
})

console.log(newArray);

EDIT: updated the answer to return sorted result based on the date;

edited Mar 3, 2020 at 20:51

answered Mar 3, 2020 at 19:50

Mechanic

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10 Comments

Mark A Avila Over a year ago

This worked pretty well! Thank You. What if I wanted to sort the array by dates instead dates value being foo and bar its "2012-03-03" and "2013-02-02" instead.

Mechanic Over a year ago

@MarkAAvila Descending or Ascending ?

Mark A Avila Over a year ago

From early to latest (2012-2020) for example

Mechanic Over a year ago

@MarkAAvila the date format matters, being timespan, being Date(), or string. what kind of date is yours?

Mark A Avila Over a year ago

the dates are with " " so strings

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