To find first word of a sentence in mongodb of specified size - mongodb

Question

I want to find the first word from a sentence(phrase) whose size is less than 3 letters.Is there any way i could find it? please suggest.
I have used
.map(function(st){return st.split(" ")[0];}
function it gives me all the first words in array format.But this is not the expected output.
{ "name" : "VAS LAYER BREED FARM PRIVATE LIMITED" }
{ "name" : "UTTARA BROILER BREED FARM PRIVATE LTD" }
{ "name" : "SAI REKHA POULTRY PRIVATE LTD" }
{ "name" : "RUHITECH NUTRITION PRIVATE LTD" }
{ "name" : "SADKAR BROILER AND AGRO FARMS PRIVATE LTD" }
{ "name" : "SADAR POULTRY PRIVATE LTD" }
From this list i need the output to print only the words: ("SAI","VAS") in the output.

Answer 1

You may perform aggregation query.
db.collection.aggregate([
{
$project: {
name: {
$let: {
vars: {
first: {
$arrayElemAt: [
{
$split: [
"$name",
" "
]
},
0
]
}
},
in: {
$cond: [
{
$lte: [
{
$strLenCP: "$$first"
},
3
]
},
"$$first",
""
]
}
}
}
}
},
{
$match: {
name: {
$ne: ""
}
}
},
{
$group: {
_id: null,
name: {
$push: "$name"
}
}
}
])
MongoPlayground

Answer 2

By what I understood from your question may be you are looking for this:
INPUT
var arr = [{ "name" : "VAS LAYER BREEDER FARM PRIVATE LIMITED" },
{ "name" : "UTTARA BROILER BREEDER FARM PRIVATE LIMITED" },
{ "name" : "SAI REKHA POULTRY FARMS PRIVATE LIMITED" }
]
CODE
var outputArr = [];
for(let j=0; j<arr.length; j++){
var chars = arr[j].name.split(' ');
for(let i=0; i<chars.length; i++){
if(chars[i].length <= 3){
outputArr.push(chars[i]);
break;
}
};
}
OUTPUT
outputArr [ 'VAS', 'SAI' ]

Answer 3

The following mongo shell query will print all the words which are less than three characters.
db.test.find().forEach( doc => {
let words = doc.name.split(" ");
for ( let word of words ) {
if ( word.length < 3 ) {
print( word );
break;
}
}
} )
The query will print the character "&".
If you want the query to print words less than or equal to three characters, change the code word.length < 3 to word.length <= 3. This will print "&","SAI" and "VAS".
If you want the query print only words with alphabets (A to Z and a to z), change ( word.length < 3 ) to ( word.length <= 3 && word.match("^[A-Za-z]+$") ). This will print "SAI" and "VAS".

Answer 4

If you want to manage the same with javascript (as your sample code suggests)
// Your question suggests you need words less than 3 length, so you can write
.map((st)=> st.split(" ")[0]).filter((str)=> str.length < 3)
// Your expected output suggests you need words less than or equal to 3 length, so you can write
.map((st)=> st.split(" ")[0]).filter((str)=> str.length <= 3)