CODEWITHSUNDEEP
javascriptstringstring-concatenation
Andrew P
Andrew P

Reputation: 1597

Joining two strings with a comma and space between them

I have been given the two strings "str1" and "str2" and I need to join them into a single string. The result should be something like this: "String1, String 2". The "str1" and "str2" variables however do not have the ", ".

So now for the question: How do I join these strings while having them separated by a comma and space?

This is what I came up with when I saw the "task", this does not seperate them with ", " though, the result for this is “String2String1”.

function test(str1, str2) {

    var res = str2.concat(str1);

    return res;

}

Upvotes: 30

Views: 140529

Answers (14)

KooiInc
KooiInc

Reputation: 122906

Here is a more generic function to concat a variable amount of string values with a separator. Includes error (type) checking.

const [str1, str2, str3, str4] = ["str1", "str2", "str3", "str4"];
console.log(concatStringsWithSeparator(str1, str2));
console.log(concatStringsWithSeparator(str1, str4, str3, str2));
console.log(concatStringsWithSeparator("!#><", str2, str1, str4));
console.log(concatStringsWithSeparator("!# => ", str1, str4, str3, str2));
console.log(concatStringsWithSeparator(`will be error`, 23, `etc`));

function concatStringsWithSeparator(...strings) {
  if ( !isArrayOfString(strings) ) {
    throw new TypeError(`...strings != Array<string>(>1)`);
  }
  
  let separator = `, `;
  
  if (strings[0].startsWith(`!#`)) {
    separator = strings[0].slice(2);
    strings = strings.slice(1);
  }
  
  return strings.join(separator);

  function isArrayOfString(input) {
    return input?.constructor === Array 
      && strings.length > 1 
      && !strings.find(s => s?.constructor !== String);
  }
}
.as-console-wrapper {
  max-height: 100% !important;
}

Upvotes: 0

Mike K.
Mike K.

Reputation: 670

It feels like a competition of evil geniuses. Let me participate:

const str1 = 'foo, bar';
const str2 = 'buzz, bux';

const mergedString = str1.split(',').concat(str2.split(',')).join(', ');
console.log(mergedString); // 'foo, bar, buzz, bux'

Upvotes: 0

StuckDuck
StuckDuck

Reputation: 21

For whoever's dealing with variables that may or may not be empty, and needs to add spacing only when necessary, this solution works for me:

let string1 = "tipo"
let string2 = ""
let string3 = "HGT"

[string1, string2, string3].filter(Boolean).join(" ")

Result:

tipo HGT

(notice the lack of the extra spaces)

Upvotes: 1

Ashita.gupta
Ashita.gupta

Reputation: 341

We should also consider the false case, if values are not present.

function joinString(str1, str2, delimiter) {
    const first = str1 || ''
    const second = str1 && str2 ? delimiter : ''
    const third = str2 || ''

    return `${first}${second}${third}`
}

console.log(joinString('A', 'B', ' ')) // Output A B
console.log(joinString('A', 'B', ',')) // Output A,B
console.log(joinString('', 'B', ' ')) // Output B
console.log(joinString('A', '', ' ')) // Output A
console.log(joinString('', '', ',')) // Output
console.log(joinString(null, '', ',')) // Output

We can write the function code in one line also but for more readability divided into small part

Other solution but it will give error if your input is empty. so always check for string is valid or not.

function joinString(str1, str2, delimiter) {
 
    return str1.concat(str1 && str2 ? delimiter : '').concat(str2)
}

console.log(joinString('A', 'B', ' ')) // Output A B
console.log(joinString('A', 'B', ',')) // Output A,B
console.log(joinString('', 'B', ' ')) // Output B
console.log(joinString('A', '', ' ')) // Output A
console.log(joinString('', '', ',')) // Output 
console.log(joinString(null, '', ',')) // Output Error

Upvotes: 0

Manish Mittal
Manish Mittal

Reputation: 1

There are a lot of way to do this:

var str1 = "Hello";
const str2 = "world!";

const result1 = str1+", "+str2;

const result2 = `${str1}, ${str2}`;

const result3 = str1.concat(", ").concat(str2);

const strings = [str1, str2];
const result4 = strings.join(", ")

Upvotes: 0

Itaca
Itaca

Reputation: 47

Google led us here, and apparently nobody mentions what we were after:

function metJoinStrings(varpString1, varpString2, varpSeparator) {
  return varpString1 + (varpString1 === '' ? '' : varpSeparator) + varpString2;
}

With this approach, the end result is presentable as expected, and consequently splittable afterwards. IMPORTANT: one could want to verify or manage the presence of 'varpSeparator' in the source strings, and act accordingly.

Also, parameter type validation should be added.

Upvotes: 1

Rui Nunes
Rui Nunes

Reputation: 848

You can also use concat() with multiple params.

a = 'car'
a.concat(', ', 'house', ', ', 'three')
// "car, house, three"

Upvotes: 2

Rahul Desai
Rahul Desai

Reputation: 15501

My trick is to use concat() twice (with chaining).

var str1 = "Hello";
var str2 = "world!";
var result = str1.concat(", ").concat(str2);
document.getElementById("demo").innerHTML=result;

Working Demo

Upvotes: 1

Mehran Hatami
Mehran Hatami

Reputation: 12961

you can easily do this:

function test(str1, str2) {
    return Array.prototype.join.call(arguments, ", ");
}

Upvotes: 2

Jyoti Prakash
Jyoti Prakash

Reputation: 1260

try this:

 function test(str1, str2) {

     var res = str2 + ',' + str1;

     return res;

 }

Upvotes: 22

Satish Sharma
Satish Sharma

Reputation: 9635

try this

function test(str1, str2) {

var res = str1+", "+str2;

return res;

}

Upvotes: 1

Zoltan.Tamasi
Zoltan.Tamasi

Reputation: 1391

That's it:

strings = ["str1", "str2"]; 
strings.join(", ");

Upvotes: 11

thefourtheye
thefourtheye

Reputation: 239453

Simply

return str1 + ", " + str2;

If the strings are in an Array, you can use Array.prototype.join method, like this

var strings = ["a", "b", "c"];
console.log(strings.join(", "));

Output

a, b, c

Upvotes: 52

Hans
Hans

Reputation: 2800

Just add the strings.

res = str1 + ', ' + str2;

Upvotes: 4

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