What's the meaning of 'trim' when use in mongoose?

Question

The link is http://mongoosejs.com/docs/api.html#schema_string_SchemaString-trim

I'm beginner in mongoosejs. I just don't get it...

I saw this question How to update mongoose default string schema property trim? but don't understand why trim. Im creating my first schema today like a 'hello world'.

I saw this to https://stackoverflow.com/tags/trim/info ... but when i need to use it, i want to learn more about it. Im looking for an explanation for a beginner...

Insensitive

Answer 1

It's basically there to ensure the strings you save through the schema are properly trimmed. If you add { type: String, trim: true } to a field in your schema, then trying to save strings like " hello", or "hello ", or " hello ", would end up being saved as "hello" in Mongo - i.e. white spaces will be removed from both sides of the string.

Electrokinetic

@bruno.karklis Read documents about javascript trim function. – Richellericher

@xpto Why this behave like that as normal javascript function won't behave the same <script> function myFunction() { var str = " Hello World! "; alert(str.trim()); } </script> <!-- This will display "Hello World!" – Waxwork

@VIKASKOHLI because in that time i dint know the JS syntax well, i was learning, my background was SQL and PHP, and the thinking process is diferent, you dont use php syntax in SQL databade to do something. Besides that i knew that the database was made in JS, i was not aware that i could use JS syntax in the database. – Insensitive

another question is that "should we really handle such things at DB level?" since it can be handled through server code. Are there any performance benefits? – Unaffected

@UndefinedBehavior It you will add " hello world", its will be "hello world" – Erikaerikson

Answer 2

Using trim will help in removing the white spaces present (beginning and ending of the string) in the string that you want to save to the DB like

"ABC " , "     ABC  ",

will be saved in the form

"ABC"

Saleable

Answer 3

trim: true

will remove leading and trailing whitespaces so something like

" hello "

will be saved as

"hello"

Begat

Answer 4

trim in Mongoose removes the space if it is at the beginning or end of the string ,

exemple : ' hello world '

when you activate trim in attribute It is saved : 'hello world'

Erb

Answer 5

trim in mongoose use to remove the white spaces from the strings

Depurative

Trim removes whitespace characters from the beginning and end of a string. – Accredit

Answer 6

Actually, we use trim in mongoose to remove white space in a string.

For example: without use trim or trim:false

"mong oose "

with use trim or trim:true

"mongoose"

Note: gain better experience to read mongoose doc.

Aplacental

As said in documentation: JavaScript strings have a trim() method that you can use to can use to remove leading and trailing whitespace from a string. Trim don't remove white space in the middle of words. so trimmed "mong oose " is "mong oose". Please check and fix – Accredit