Is there any way to create mongodb like _id strings without mongodb? - javascript

I really like the format of the _ids generated by mongodb. Mostly because I can pull data like the date out of them client side. I'm planning to use another database but still want that type of _id for my document. How can I create these ids without using mongodb?
Thanks!


A very easy pseudo ObjectId generator in javascript:
const ObjectId = (m = Math, d = Date, h = 16, s = s => m.floor(s).toString(h)) =>
s(d.now() / 1000) + ' '.repeat(h).replace(/./g, () => s(m.random() * h))


Use the official MongoDB BSON lib in the client
I have a browser client that generates ObjectIds. I wanted to make sure that I employ the same ObjectId algorithm in the client as the one used in the server. MongoDB has js-bson which can be used to accomplish that.
If you are using javascript with node.
npm install --save bson
Using require statement
var ObjectID = require('bson').ObjectID;
var id = new ObjectID();
console.log(id.toString());
Using ES6 import statement
import { ObjectID } from 'bson';
const id = new ObjectID();
console.log(id.toString());
The library also lets you import using good old script tags but I have not tried this.


Object IDs are usually generated by the client, so any MongoDB driver would have code to generate them.
If you're looking for JavaScript, here's some code from the MongoDB Node.js driver:
https://github.com/mongodb/js-bson/blob/1.0-branch/lib/bson/objectid.js
And another, simpler solution:
https://github.com/justaprogrammer/ObjectId.js


Extending Rubin Stolk's and ChrisV's answer in a more readable syntax (KISS).
function objectId () {
return hex(Date.now() / 1000) +
' '.repeat(16).replace(/./g, () => hex(Math.random() * 16))
}
function hex (value) {
return Math.floor(value).toString(16)
}
export default objectId


ruben-stolk's answer is great, but deliberately opaque? Very slightly easier to pick apart is:
const ObjectId = (rnd = r16 => Math.floor(r16).toString(16)) =>
rnd(Date.now()/1000) + ' '.repeat(16).replace(/./g, () => rnd(Math.random()*16));
(actually in slightly fewer characters). Kudos though!


This is a simple function to generate a new objectId
newObjectId() {
const timestamp = Math.floor(new Date().getTime() / 1000).toString(16);
const objectId = timestamp + 'xxxxxxxxxxxxxxxx'.replace(/[x]/g, () => {
return Math.floor(Math.random() * 16).toString(16);
}).toLowerCase();
return objectId;
}


Here's a link! to a library to do that.
https://www.npmjs.com/package/mongo-object-reader
You can read and write hexadecimal strings.
const { createObjectID, readObjectID,isValidObjectID } = require('mongo-object-reader');
//Creates a new immutable `ObjectID` instance based on the current system time.
const ObjectID = createObjectID() //a valid 24 character `ObjectID` hex string.
//returns boolean
// input - a valid 24 character `ObjectID` hex string.
const isValid = isValidObjectID(ObjectID)
//returns an object with data
// input - a valid 24 character `ObjectID` hex string.
const objectData = readObjectID(ObjectID)
console.log(ObjectID) //ObjectID
console.log(isValid) // true
console.log(objectData) /*
{ ObjectID: '5e92d4be2ced3f58d92187f5',
timeStamp:
{ hex: '5e92d4be',
value: 1586681022,
createDate: 1970-01-19T08:44:41.022Z },
random: { hex: '2ced3f58d9', value: 192958912729 },
incrementValue: { hex: '2187f5', value: 2197493 } }
*/


There is a detailed specification here
http://www.mongodb.org/display/DOCS/Object+IDs
Which you can use to roll your own id strings

Related

Javascript JSON.stringify method removes trailing zero if object has value as x.0 ( like 6.0 ) [duplicate]

I am working on a project where I require to format incoming numbers in the following way:
###.###
However I noticed some results I didn't expect.
The following works in the sense that I don't get an error:
console.log(07);
// or in my case:
console.log(007);
Of course, it will not retain the '00' in the value itself, since that value is effectively 7.
The same goes for the following:
console.log(7.0);
// or in my case:
console.log(7.000);
JavaScript understands what I am doing, but in the end the actual value will be 7, which can be proven with the following:
const leadingValue = 007;
const trailingValue = 7.00;
console.log(leadingValue, trailingValue); // both are exactly 7
But what I find curious is the following: the moment I combine these two I get a syntax error:
// but not this:
console.log(007.000);
1) Can someone explain why this isn't working?
I'm trying to find a solution to store numbers/floats with the exact precision without using string.
2) Is there any way in JS/NodeJS or even TypeScript to do this without using strings?
What I currently want to do is to receive the input, scan for the format and store that as a separate property and then parse the incoming value since parseInt('007.000') does work. And when the user wants to get this value return it back to the user... in a string.. unfortunately.

1) 007.000 is a syntax error because 007 is an octal integer literal, to which you're then appending a floating point part. (Try console.log(010). This prints 8.)
2) Here's how you can achieve your formatting using Intl.NumberFormat...
var myformat = new Intl.NumberFormat('en-US', {
minimumIntegerDigits: 3,
minimumFractionDigits: 3
});
console.log(myformat.format(7)); // prints 007.000

Hi
You can use an aproach that uses string funtions .split .padStart and .padEnd
Search on MDN
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/split
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/padStart
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/padEnd
Here you have an example:
const x = 12.1;
function formatNumber( unformatedNumber) {
const desiredDecimalPad = 3;
const desiredNonDecimalPad = 3;
const unformatedNumberString = unformatedNumber.toString();
const unformatedNumberArr = unformatedNumberString.split('.');
const decimalStartPadded = unformatedNumberArr[0].padStart(desiredDecimalPad, '0');
const nonDecimalEndPadded = unformatedNumberArr[1].padEnd(desiredNonDecimalPad, '0');
const formatedNumberString = decimalStartPadded + '.' + nonDecimalEndPadded;
return formatedNumberString;
}
console.log(formatNumber(x))

How do you truncate a String to a max number of bytes in Google Apps Script?

I am parsing a JSON object obtained by URLFetchApp.fetch() and need to truncate a string value to a max number of bytes. It seems like some combination of the Google Apps Script Utilities Class and HTTPResponse Class is where I will find the answer, but I can not figure out which methods to use and how to put them together.
{object: {key: 'string'}}
something like:
object.key.string.toBytes().substringAsBytes(0,maxBytes).backToString()
https://developers.google.com/apps-script/reference/utilities
https://developers.google.com/apps-script/reference/url-fetch/http-response

Use with Array.splice:
const str = { obj: { key: 'string' } }.obj.key,
maxBytes = 10,
byteData = Utilities.newBlob(str).getBytes();
byteData.splice(maxBytes);
const truncatedStr = Utilities.newBlob(byteData).getDataAsString();

How to insert a long/BigInt with Node.js MongoDB Driver?

I try to insert a long/BigInt into my MongoDB Database with the Node.js Mongo Driver.
I've already tried with BigInt, but it doesn't insert the number (expiry) in the document.
let expire = BigInt(parseInt((Date.now() / 1000) + 21600, 10));
let newDoc = {
type: "group.test",
expiry: expire
};
collection.insertOne(newDoc);
// it only inserts the type.
I want it to save as BigInt because we need to get it later with a Java Server.

BigInt is an object in JS you can't just pass it to Mongodb. Take a look at the data types supported by Mongodb.
https://docs.mongodb.com/manual/reference/bson-types/
I would suggest storing the BigInt as string in mongodb and let the reader parse it when the document is read.
// Note: this function is a simple serializer
// meant to demo the concept.
function bigIntSerializer(num){
return {
type: "BigInt",
value: num.toString()
};
}
let expire = BigInt(parseInt((Date.now() / 1000) + 21600, 10));
let newDoc = {
type: "group.test",
expiry: bigIntSerializer(expire)
};
collection.insertOne(newDoc);

use Long
https://mongodb.github.io/node-mongodb-native/3.5/api/Long.html
const { Long } = require('mongodb');
let expire = BigInt(parseInt((Date.now() / 1000) + 21600, 10));
let newDoc = {
type: "group.test",
expiry: new Long(Number(expire & 0xFFFFFFFFn), Number((expire >> 32n) & 0xFFFFFFFFn))
};

In JavaScript Google Flatbuffers, how does one write a ulong?

I have no problem with doing this in a C++ program, but I am stuck on writing a ulong in JS.
FB has no issue if I used the 32bit process.hrtime() value.
But how does do a createLong() for a 64bit ?
see: [ https://nodejs.org/api/process.html#process_process_hrtime_bigint ]
# commented line does not work
# let timeStamp = process.hrtime.bigint()
let timeStamp = process.hrtime()
let ts = builder.createLong(0, timeStamp)
PNT.Telemetry.startTelemetry(builder)
PNT.Telemetry.addSystemTime(builder, ts)
FB template file
// Simple Telemetry data from/to Sim and Sensor
namespace PNT;
enum DeviceType:byte { IMU, VAN, GPS, MAGNAV, SOOP }
struct PosVector {
lat:double;
lon:double;
alt:double;
}
table Telemetry {
source: string;
systemTime:ulong = 0;
systemTimeString: string;
description: string;
position: PosVector;
}
root_type Telemetry;

You can use this function, it works well for timestamp
var flatBufferTimeStamp = function(value) {
var bin = (value).toString(2);
var pad = new Array(64 - bin.length + 1 ).join('0');
bin = pad + bin;
return {
low: parseInt(bin.substring(32), 2),
high: parseInt(bin.substring(0, 32), 2)
};
}
var timeStamp = flatBufferTimeStamp(process.hrtime())
let ts = builder.createLong(timeStamp.low, timeStamp.high);
PNT.Telemetry.startTelemetry(builder)
PNT.Telemetry.addSystemTime(builder, ts)
Source: https://groups.google.com/forum/#!topic/flatbuffers/ieXNEsB_2wc

Use flatbuffers.Long, here is an example: https://github.com/google/flatbuffers/blob/master/tests/JavaScriptTest.js#L160
Sadly there is no code in FlatBuffers to convert a bigint to the 2 32-bit values, which would be good to add. For now you may need to do your own conversion.

Convert ObjectID (Mongodb) to String in JavaScript

I want to convert ObjectID (Mongodb) to String in JavaScript.
When I get a Object form MongoDB. it like as a object has: timestamp, second, inc, machine.
I can't convert to string.

Try this:
objectId.str
See the doc.
ObjectId() has the following attribute and methods:
[...]
str - Returns the hexadecimal string representation of the object.

in the shell
ObjectId("507f191e810c19729de860ea").str
in js using the native driver for node
objectId.toHexString()

Here is a working example of converting the ObjectId in to a string
> a=db.dfgfdgdfg.findOne()
{ "_id" : ObjectId("518cbb1389da79d3a25453f9"), "d" : 1 }
> a['_id']
ObjectId("518cbb1389da79d3a25453f9")
> a['_id'].toString // This line shows you what the prototype does
function () {
return "ObjectId(" + tojson(this.str) + ")";
}
> a['_id'].str // Access the property directly
518cbb1389da79d3a25453f9
> a['_id'].toString()
ObjectId("518cbb1389da79d3a25453f9") // Shows the object syntax in string form
> ""+a['_id']
518cbb1389da79d3a25453f9 // Gives the hex string
Did try various other functions like toHexString() with no success.

You can use $toString aggregation introduced in mongodb version 4.0 which converts the ObjectId to string
db.collection.aggregate([
{ "$project": {
"_id": { "$toString": "$your_objectId_field" }
}}
])

Use toString:
var stringId = objectId.toString()
Works with the latest Node MongoDB Native driver (v3.0+):
http://mongodb.github.io/node-mongodb-native/3.0/

Acturally, you can try this:
> a['_id']
ObjectId("518cbb1389da79d3a25453f9")
> a['_id'] + ''
"518cbb1389da79d3a25453f9"
ObjectId object + String will convert to String object.

If someone use in Meteorjs, can try:
In server: ObjectId(507f191e810c19729de860ea)._str.
In template: {{ collectionItem._id._str }}.

Assuming the OP wants to get the hexadecimal string value of the ObjectId, using Mongo 2.2 or above, the valueOf() method returns the representation of the object as a hexadecimal string. This is also achieved with the str property.
The link on anubiskong's post gives all the details, the danger here is to use a technique which has changed from older versions e.g. toString().

In Javascript, String() make it easy
const id = String(ObjectID)

this works, You have mongodb object: ObjectId(507f191e810c19729de860ea),
to get string value of _id, you just say
ObjectId(507f191e810c19729de860ea).valueOf();

In Js do simply: _id.toString()
For example:
const myMongoDbObjId = ObjectID('someId');
const strId = myMongoDbObjId.toString();
console.log(typeof strId); // string

You can use string formatting.
const stringId = `${objectId}`;

toString() method gives you hex String which is kind of ascii code but in base 16 number system.
Converts the id into a 24 character hex string for printing
For example in this system:
"a" -> 61
"b" -> 62
"c" -> 63
So if you pass "abc..." to get objectId you will get "616263...".
As a result if you want to get readable string(char string) from objectId you have to convert it(hexCode to char).
To do this I wrote an utility function hexStringToCharString()
function hexStringToCharString(hexString) {
const hexCodeArray = [];
for (let i = 0; i < hexString.length - 1; i += 2) {
hexCodeArray.push(hexString.slice(i, i + 2));
}
const decimalCodeArray = hexCodeArray.map((hex) => parseInt(hex, 16));
return String.fromCharCode(...decimalCodeArray);
}
and there is usage of the function
import { ObjectId } from "mongodb";
const myId = "user-0000001"; // must contains 12 character for "mongodb": 4.3.0
const myObjectId = new ObjectId(myId); // create ObjectId from string
console.log(myObjectId.toString()); // hex string >> 757365722d30303030303031
console.log(myObjectId.toHexString()); // hex string >> 757365722d30303030303031
const convertedFromToHexString = hexStringToCharString(
myObjectId.toHexString(),
);
const convertedFromToString = hexStringToCharString(myObjectId.toString());
console.log(`convertedFromToHexString:`, convertedFromToHexString);
//convertedFromToHexString: user-0000001
console.log(`convertedFromToString:`, convertedFromToString);
//convertedFromToHexString: user-0000001
And there is also TypeScript version of hexStringToCharString() function
function hexStringToCharString(hexString: string): string {
const hexCodeArray: string[] = [];
for (let i = 0; i < hexString.length - 1; i += 2) {
hexCodeArray.push(hexString.slice(i, i + 2));
}
const decimalCodeArray: number[] = hexCodeArray.map((hex) =>
parseInt(hex, 16),
);
return String.fromCharCode(...decimalCodeArray);
}

Just use this : _id.$oid
And you get the ObjectId string. This come with the object.

Found this really funny but it worked for me:
db.my_collection.find({}).forEach((elm)=>{
let value = new String(elm.USERid);//gets the string version of the ObjectId which in turn changes the datatype to a string.
let result = value.split("(")[1].split(")")[0].replace(/^"(.*)"$/, '$1');//this removes the objectid completely and the quote
delete elm["USERid"]
elm.USERid = result
db.my_collection.save(elm)
})

On aggregation use $addFields
$addFields: {
convertedZipCode: { $toString: "$zipcode" }
}

Documentation of v4 (right now it's latest version) MongoDB NodeJS Driver says: Method toHexString() of ObjectId returns the ObjectId id as a 24 character hex string representation.

In Mongoose, you can use toString() method on ObjectId to get a 24-character hexadecimal string.
Mongoose documentation

Below three methods can be used to get the string version of id.
(Here newUser is an object containing the data to be stored in the mongodb document)
newUser.save((err, result) => {
if (err) console.log(err)
else {
console.log(result._id.toString()) //Output - 23f89k46546546453bf91
console.log(String(result._id)) //Output - 23f89k46546546453bf91
console.log(result._id+"") //Output - 23f89k46546546453bf91
}
});

Use this simple trick, your-object.$id
I am getting an array of mongo Ids, here is what I did.
jquery:
...
success: function (res) {
console.log('without json res',res);
//without json res {"success":true,"message":" Record updated.","content":[{"$id":"58f47254b06b24004338ffba"},{"$id":"58f47254b06b24004338ffbb"}],"dbResponse":"ok"}
var obj = $.parseJSON(res);
if(obj.content !==null){
$.each(obj.content, function(i,v){
console.log('Id==>', v.$id);
});
}
...

You could use String
String(a['_id'])

If you're using Mongoose along with MongoDB, it has a built-in method for getting the string value of the ObjectID. I used it successfully to do an if statement that used === to compare strings.
From the documentation:
Mongoose assigns each of your schemas an id virtual getter by default which returns the document's _id field cast to a string, or in the case of ObjectIds, its hexString. If you don't want an id getter added to your schema, you may disable it by passing this option at schema construction time.

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