Remove "null" from string in javascript

Question

I have this code:

var returnValue = item.fname + " " + item.mname + " " + item.lname
returnValue.replace(null," ");
return returnValue ;

Sometimes one of the fields is null so returnValue is:

"John null Doe"

or

"John something null"

I want to get rid of the "null" but my code does not seem to work.

Can someone help me out here?

returnValue.replace('null'," ");? Replace the null object, with null as a string — BritishWerewolf
– BritishWerewolf, Commented Oct 19, 2018 at 12:40
Instead of removing null afterwards, add a check to your fields and only add them if they are not null to avoid the issue alltogether. Otherwise, what would happen if someones name is 'Joe Nullmann'? — Rence
– Rence, Commented Oct 19, 2018 at 12:40
@Sirence He'll become 'Joe mann' and may finally get a value out of his name — D.Schaller
– D.Schaller, Commented Oct 19, 2018 at 14:00

James Monger · Accepted Answer · 2018-10-19 12:49:18Z

4

Rather than replacing null afterwards, only append the individual names if they are not null.

var returnValue = "";

if (item.fname !== null) {
    returnValue += item.fname + " ";
}

if (item.mname !== null) {
    returnValue += item.mname + " ";
}

if (item.lname !== null) {
    returnValue += item.lname;
}

return returnValue;

Alternatively, use Array.prototype.filter to remove nulls:

// store the names in an array
var names = [ item.fname, item.mname, item.lname ];

// filter the array to values where they are `!== null`
var notNullNames = names.filter(x => x !== null);

// join them with spaces
var returnValue = notNullNames.join(" ");

edited Oct 19, 2018 at 12:49

answered Oct 19, 2018 at 12:41

James Monger

10.8k9 gold badges65 silver badges99 bronze badges

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

Comments

Matthi · Accepted Answer · 2018-10-19 12:42:22Z

1

var returnValue = (item.fname || " ") + " " + (item.mname || " ") + " " + (item.lname || " ");
return returnValue;

Be careful with mixing var types (string and null for example). Better make sure the variable is set or has a fallback.

answered Oct 19, 2018 at 12:42

Matthi

1,0738 silver badges19 bronze badges

Comments

Eugene Tsakh · Accepted Answer · 2018-10-19 12:43:16Z

1

I'd recommend you another technique: place your string parts to array, filter it and join it:

[item.fname, item.mname, item.lname].filter(v => !!v).join(' ')

answered Oct 19, 2018 at 12:43

Eugene Tsakh

2,8812 gold badges18 silver badges28 bronze badges

5 Comments

Nina Scholz Over a year ago

you could filter with Boolean as cb.

Eugene Tsakh Over a year ago

@NinaScholz it's not recommended, as filter callback receives 3 arguments: currentElement, index, array while Boolean accepts just 1.

Andreas Over a year ago

"it's not recommended" - Why? Boolean() will just ignore the additional arguments

Eugene Tsakh Over a year ago

@Andreas that's the problem of JS and that's why big companies are using Flow and TypeScript. It's misuse of API. If it accepts a single param then you should pass only a single param

Nina Scholz Over a year ago

but you are using only one parameter as well.

ShabbirAli · Accepted Answer · 2018-10-23 06:40:03Z

0

try this

>    return (item.fname ? item.fname : '')  + " " + (item.mname ? item.mname : '') + " " + (item.lname ? item.lname : '');

edited Oct 23, 2018 at 6:40

answered Oct 19, 2018 at 12:48

ShabbirAli

241 bronze badge

1 Comment

hacking_mike Over a year ago

This one did it for me. Thanks

hossein sedighian · Accepted Answer · 2018-10-19 12:42:41Z

0

var returnValue = item.fname

if(item.mname)returnValue  += " " + item.mname

 if(item.lname)returnValue  += " " + item.lname

return returnValue

answered Oct 19, 2018 at 12:42

hossein sedighian

2,1901 gold badge17 silver badges21 bronze badges

1 Comment

Blue Over a year ago

Thank you for this code snippet, which might provide some limited, immediate help. A proper explanation would greatly improve its long-term value by showing why this is a good solution to the problem, and would make it more useful to future readers with other, similar questions. Please edit your answer to add some explanation, including the assumptions you've made.

Sdwdaw · Accepted Answer · 2018-10-19 12:47:10Z

0

Try ternary operator for null avoiding:

var returnValue = item.fname + " " + item.mname ? item.mname : "" + " " + item.lname

answered Oct 19, 2018 at 12:47

Sdwdaw

1,0377 silver badges14 bronze badges

Comments

Christian Vincenzo Traina · Accepted Answer · 2018-10-19 13:57:56Z

0

In my opinion, the most elegant solution is:

[item.fname, item.lname, item.lname].join(' ');

For example:

const item = {}
item.fname = 'foo'
item.lname = 'bar'

console.log([item.fname, item.mname, item.lname].join(' '))

Otherwise you can use the or operator to skip falsy objects:

const item = {}
item.fname = 'foo'
item.lname = 'bar'

const joined = (item.fname || '') + " " + (item.mname || '') + " " + (item.lname || '')

console.log(joined)

answered Oct 19, 2018 at 13:57

Christian Vincenzo Traina

10.6k4 gold badges45 silver badges79 bronze badges

Collectives™ on Stack Overflow

Remove "null" from string in javascript

7 Answers 7

Comments

Comments

5 Comments

1 Comment

1 Comment

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

7 Answers 7

Comments

Comments

5 Comments

1 Comment

1 Comment

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related