pipeline with $match not work as per expectation on mongodb - node.js

Question

I have tried to do somthing like this join and search. I'm trying to do a search with in side pipeline with $match, but the issue is that $match is not working.
it is not searching or join two collections.
SELECT * FROM `post`
Left JOIN postcat ON post.id=postcat.postid
Left JOIN catagory ON postcat.catid=catagory.id
WHERE
post_name LIKE '%a%'
OR post_data LIKE '%some data%'
OR tags LIKE '%some data%'
OR post_url LIKE '%some data%'
This is my collection info
Post
{
"_id" : ObjectId("5d29bd7609f28633f38ccc13"),
"postname" : "this is some data",
"tags" : "Damita,Caro",
"postdata" : "Berry Roseline Lira Cristy Hedi Clem Nerissa ",
"catagory" : [ {
"catagory_id" : [
ObjectId("5d29bd7509f28633f38ccbfd")
]
}, {
"catagory_id" : [
ObjectId("5d29bd7509f28633f38ccbfd")
]
}
],
"createby" : "5d22f712fe481b2a9afda4aa"
} ..........
category
{
"_id" : ObjectId("5d29bc271a68fb333531f6a1"),
"catagory_name" : "Katharine",
"catagory_description" : "Katharine"
}
The code i have tried so far:
var search_data = "some data";
var search_limit = 10;
var search_skip = 0;
db.collection.aggregate([
{
$lookup: {
let: {
post_id: "$catagory.catagory_id" ,
postname: "$postname",
posturl: "$posturl" ,
postdata: "$postdata" ,
tags: "$tags"
},
from: 'catagories',
pipeline: [
{
$match: {
$expr: {
$and: [
{ $eq: ["$_id", "$$post_id"] },
{
$or: [
{"$$catagory_name": { $regex: new RegExp(search_data, 'i')}},
{"$$postname": { $regex: `^${search_data}` } },
{"$$posturl": { $regex: new RegExp(search_data, 'i') }},
{"$$postdata": { $regex: new RegExp(search_data, 'i') }},
{"$$tags": { $regex: new RegExp(search_data, 'i') }}
]
}
]
}
}
}
],
as: "catagories_data"
}
},
{ $limit : search_limit },
{ $skip : search_skip },
{ $group : { _id : "$_id", postname: { $push: "$postname" } } }
]).expla(function (err, data_post)
{
console.log(err);
console.log(data_post);
})
i have no idea how to fix it. any suggestion on it