Sort array of object if value exists

Question

Below is my sort function but I want to display the ones with a code to be at the top. I want to sort my array of objects by code, then by description. Right now, the items without a code is being placed at the top of the order.

data = [
 {
  code: "1.1",
  description: "aaa"
 },
 {
  code: "",
  description: "bbb"
 },
 {
  code: "1.2",
  description: "ccc"
 }
]


  let sortedData = data.sort(function(a, b) {
    let codeA = a.code
    let codeB = b.code
    let descriptionA = a.description.toLowerCase()
    let descriptionB = b.description.toLowerCase()

    if (codeA < codeB) return -1
    if (codeA > codeB) return 1
    if (descriptionA < descriptionB) return -1
    if (descriptionA > descriptionB) return 1
    return 0
  })

  return sortedData

Current order:

["bbb", "aaa", "ccc"]

Expected order:

["aaa", "ccc", "bbb"]

Taplar · Accepted Answer · 2019-02-12 23:49:58Z

4

Using the xor ^ operator, we can check to see if one of the codes is falsy while the other is truthy. In this case, falsy being blank. If this is true, the one with a blank should be greater than the other so it sorts after it.
Otherwise, subtract the codes, then the descriptions for normal sorting.

var data = [
 {
  code: "1.1",
  description: "aaa"
 },
 {
  code: "",
  description: "bbb"
 },
 {
  code: "1.2",
  description: "ccc"
 }
];


  let sortedData = data.sort(function(a, b) {
    let codeA = a.code;
    let codeB = b.code;
    let descriptionA = a.description.toLowerCase();
    let descriptionB = b.description.toLowerCase();
    
    if (codeA ^ codeB) {
      return !codeA ? 1 : -1;
    }
    
    return codeA.localeCompare(codeB) || descriptionA.localeCompare(descriptionB);
  });

  console.log(sortedData)

edited Feb 12, 2019 at 23:49

answered Feb 12, 2019 at 23:04

Taplar

25k4 gold badges24 silver badges36 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Mark Over a year ago

What does 'aaa' - 'bbb' equal? This does not sort the description strings correctly in cases where the code is equal. It looks like it works because they are already sorted.

Taplar Over a year ago

@MarkMeyer fixed it to use the localeCompare properly.

Keith · Accepted Answer · 2019-02-12 23:13:43Z

One way to make "" appear at the end is just to prefix the compare values, so if the code is "", the value becomes "B", if it's 1.1 it become A1.1, so A1.1 < B..

Doing this is also very easy to modify to do all sort of fancy sorting, eg. Lets say you wanted to sort alphabetically, but wanted all K's at the start, and all B's at the end, strange thing to do. But very easy to make happen. I suppose you could call it sorting with exceptions.

Here is a working example.

const data = [
 {
  code: "1.1",
  description: "aaa"
 },
 {
  code: "",
  description: "bbb"
 },
 {
  code: "1.2",
  description: "ccc"
 }
];

data.sort((
  { code: code1, description: desc1 },
  { code: code2, description: desc2 }
) => {
  code1 = (code1 === "" ? "B" : "A") + code1;
  code2 = (code2 === "" ? "B" : "A") + code2;
  return code1.localeCompare(code2) ||
    desc1.localeCompare(desc2);
});


console.log(data);

Mark · Accepted Answer · 2019-02-12 23:19:40Z

Your test case is a little lax and makes it hard to spot some bugs. You are usually better off using localeCompare to compare strings. You can make a case for two very plain, but readable if statements followed by a localeCompare of the strings:

Here's a few extra test cases

let data = [{
    code: "1.1",
    description: "ddd"
  },
  {
    code: "1.101",
    description: "ccc"
  },
  {
    code: "",
    description: "eee"
  },
  {
    code: "1.2",
    description: "De"
  },
  {
    code: "1.1",
    description: "aaa"
  },
  {
    code: "",
    description: "bbb"
  },
  {
    code: "1.2",
    description: "ccc"
  },
  {
    code: "1.2",
    description: "AbcD"
  }
]

data.sort((a, b) => {
  if (a.code && !b.code) return -1
  if (b.code && !a.code) return 1

  return a.code.localeCompare(b.code) || a.description.localeCompare(b.description)
})
console.log(data)

:

Alberti Buonarroti · Accepted Answer · 2019-02-12 23:20:06Z

0

Since your second code is empty you will compare an empty string and Javascript will cast your Float to a String. Oddly if you compare any string if it is smaller than any other string it will always return true! The opposite is also true - if you compare it to be bigger than any other string it will always return false.

"" < "1.1" // return true
"1.1" < "" // return true!

"" > "1.1" // return false
"1.1" > "" // return false!

To solve your problem you could add two additional checks before your other checks

if (codeA === "" && codeA.length < codeB.length) return 1;
if (codeB === "" && codeA.length > codeB.length) return -1;

If codeA or codeB is a String you can simply compare the length of the strings.

edited Feb 12, 2019 at 23:20

answered Feb 12, 2019 at 23:12

Alberti Buonarroti

4493 silver badges9 bronze badges

Collectives™ on Stack Overflow

Sort array of object if value exists

4 Answers 4

2 Comments

Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

4 Answers 4

2 Comments

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related