Develop Reference

how do I check if a value is in a JSON return or not?

I'm writing a test in postman where I want to check if a JSON return contains the Label called 'RegressieMapTest'. This is my script:
pm.test("Is the folder created correctly?", function(){
var jsonData = pm.response.json();
var objString = JSON.stringify(jsonData);
var obj = JSON.parse(objString);
for (var i = 0; i < obj.Corsa.Data.length; i++){
if (obj.Corsa.Data[i].Label == "RegressieMapTest"){
console.log(obj.Corsa.Data[i].Label);
pm.expect(obj.Corsa.Data.Label).to.eql("RegressieMapTest");
}
}
pm.expect.fail();
})
But it doesn't quite work, every time I run this script it seems like it automatically jumps to pm.expect.fail() which is weird because 'RegressieMapTest' is inside the JSON return. Postman returns the following message:
Is the folder created correctly? | AssertionError: expect.fail()

pm.respose.json() is equalent to JSON.parse you don't have to do it again
also you can use array.find method instead of looping through it
pm.test("Is the folder created correctly?", function () {
var jsonData = pm.response.json();
pm.expect(obj.Corsa.Data.find(elem => elem.Label === "RegressieMapTest")).to.be.not.undefined
}
if array has any element with label RegressieMapTest then it will return that data elese returns undefined, so we are validating that it will not return undefined. Meaning it has the value

Your pm.expect.fail(); always runs. You want it to run only when you don't find the field. So just add a flag in your check block.
pm.test("Is the folder created correctly?", function(){
var jsonData = pm.response.json();
var objString = JSON.stringify(jsonData);
var obj = JSON.parse(objString);
var isFound = false;
for (var i = 0; i < obj.Corsa.Data.length; i++){
if (obj.Corsa.Data[i].Label == "RegressieMapTest"){
console.log(obj.Corsa.Data[i].Label);
pm.expect(obj.Corsa.Data.Label).to.eql("RegressieMapTest");
isFound = true;
}
}
if (!isFound) {
pm.expect.fail();
}
})

Best practice to handle undefined variables dynamicaly in JavaScript/Nodejs

Ok, maybe is not the best title, but I lacked inspiration, so here goes:
Let's say you have a "global" (not really) variable to store temporary data and sub data as random users interact with your server. Normally on the first interaction with your server, the main variable will be undefined so you need to handle that case.
Now, what puzzled me about this, is what's the best practice performance wise to do this if there are a lot of users and a lot way more interactions with the variable.
Puzzled? Yeah, I know, words are not my strong point so let me show you in code
So you have
var user_data = [];
Then a function that handles user interaction to store data
function writeData(uid, data_name, data)
Now, on first interaction, user_data[uid][data_name] is undefined, and so it's user_data[uid]
I know you can handle this 2 ways:
With if -
if(!user_data[uid]) user_data[uid] = {}
user_data[uid][data_name] = data
With try/catch
try{user_data[uid][data_name] = data}
catch(e) {user_data[uid] = {}; writeData(uid, data_name, data)}
The if will check on every interaction, and like I said there are a lot.
Try catch will trigger once, but it has a cost as a block (afaik)
Which one is better? Or is there a another better way

#Nertan ,
There is a partiality in your proof :P . I have slightly tweeked the ternary way (same as the order of execution in if way). With this you can conclude.
//var present = require('present');
function test(val,ud,fun) {
var k = 10000000;
var t = Date.now();
for(var i=0; i<k;i++)
{
var uid = Math.ceil(Math.random()*1000);
fun(uid,ud,"value");
}
var tf = Date.now()-t;
return tf;
}
function setValue_Opp(uid,ud,value)
{
(!ud[uid] && (ud[uid] = {})) && (ud[uid].value = value);
}
function setValue_Try(uid,ud,value)
{
try{ ud[uid].value = value}
catch(e){ ud[uid] = {}; setValue_Try(uid,ud,value)};
}
function setValue_Cond(uid,ud,value)
{
if(!ud[uid]) ud[uid] = {}
ud[uid].value = value;
}
var k1=0;
var k2=0;
var k3=0;
for(var i=0;i<10;i++){
k1+=test(1,{}, setValue_Cond);
k2+=test(2,{}, setValue_Try);
k3+=test(3,{}, setValue_Opp);
}
console.log(k1,k2,k3)

I feel we can take advantage of ES6 ternaries as below:
let user_data = {}
const writeData = (uid, data_name, data) => {
((user_data[uid] || (user_data[uid] = {})) && (user_data[uid][data_name] = data ))
console.log(user_data)
// perform write action
}
writeData('1',"test","test1");
writeData('2',"test","test2");
writeData('1',"test","test3");

Ok, so I had to rewrite the test because it doesn't work fine in the Snippet
So I made this for node.js:
var present = require('present');
function test(val,ud,fun) {
var k = 10000000;
var t = present();
for(var i=0; i<k;i++)
{
var uid = Math.ceil(Math.random()*1000);
fun(uid,ud,"value");
}
var tf = present()-t;
console.log("END "+val+" at "+tf);
return tf;
}
function setValue_Opp(uid,ud,value)
{
(ud[uid] || (ud[uid] = {})) && (ud[uid].value = value);
}
function setValue_Try(uid,ud,value)
{
try{ ud[uid].value = value}
catch(e){ ud[uid] = {}; setValue_Try(uid,ud,value)};
}
function setValue_Cond(uid,ud,value)
{
if(!ud[uid]) ud[uid] = {}
ud[uid].value = value;
}
var k1=0;
var k2=0;
var k3=0;
for(var i=0;i<10;i++){
k1+=test(1,{}, setValue_Cond);
k2+=test(2,{}, setValue_Try);
k3+=test(3,{}, setValue_Opp);
}
console.log(k1,k2,k3)
And in the end:
3244.328997004777 3695.0267750024796 3437.6855720058084
Which means:
The best is the classical if
The second best is condintional operators method
And the worst is the try-catch
So it seems the classics win
Edited:
With further tests thanks to #CRayen the best method is :
(!ud[uid] && (ud[uid] = {})) && (ud[uid].value = value);

How to get utility function from helper file on node.js server?

I have a node/express server and I'm trying to get a function from a helper file to my app.js for use. Here is the function in the helper file:
CC.CURRENT.unpack = function(value)
{
var valuesArray = value.split("~");
var valuesArrayLenght = valuesArray.length;
var mask = valuesArray[valuesArrayLenght-1];
var maskInt = parseInt(mask,16);
var unpackedCurrent = {};
var currentField = 0;
for(var property in this.FIELDS)
{
if(this.FIELDS[property] === 0)
{
unpackedCurrent[property] = valuesArray[currentField];
currentField++;
}
else if(maskInt&this.FIELDS[property])
{
//i know this is a hack, for cccagg, future code please don't hate me:(, i did this to avoid
//subscribing to trades as well in order to show the last market
if(property === 'LASTMARKET'){
unpackedCurrent[property] = valuesArray[currentField];
}else{
unpackedCurrent[property] = parseFloat(valuesArray[currentField]);
}
currentField++;
}
}
return unpackedCurrent;
};
At the bottom of that helper file I did a module.export (The helper file is 400 lines long and I don't want to export every function in it):
module.exports = {
unpackMessage: function(value) {
CCC.CURRENT.unpack(value);
}
}
Then in my app.js I called
var helperUtil = require('./helpers/ccc-streamer-utilities.js');
and finally, I called that function in app.js and console.log it:
res = helperUtil.unpackMessage(message);
console.log(res);
The problem is that the console.log gives off an undefined every time, but in this example: https://github.com/cryptoqween/cryptoqween.github.io/tree/master/streamer/current (which is not node.js) it works perfectly. So I think I am importing wrong. All I want to do is use that utility function in my app.js

The unPackMessage(val) call doesn't return anything:
module.exports = {
unpackMessage: function(value) {
CCC.CURRENT.unpack(value);
}
}
you need to return CCC.CURRENT.UNPACK(value);
module.exports = {
unpackMessage: function(value) {
return CCC.CURRENT.unpack(value);
}
}

Calling forEach on Dictionary in Node.js

I am trying to loop over a Firebase reference. It works but for some reason the forEach loop runs one more time than there are objects in the reference. This causes the Promise.all() function to fail and the whole promise to fail. Here is my code. I have no Idea what I'm doing wrong.
return userReceiptMetrics.child(userID).child('postItemIDs').orderByChild('itemID').equalTo(oldProductID).once('value', function(oldSnapshot) {
var oldPostItemIDs = [];
var metrics = oldSnapshot.val()
if (oldSnapshot.val() != null) {
return Promise.all(oldSnapshot.forEach(function(record) {
console.log(record.val());
var oldKey = record.key;
var newKey = oldKey.replace(oldProductID, newProductID);
var data = record.val();
oldPostItemIDs.push(oldKey);
data.itemID = newProductID;
updateObject['userReceiptMetrics/'+userID+'/postItemIDs/'+newKey] = data;
updateObject['userReceiptMetrics/'+userID+'/postItemIDs/'+oldKey] = null;
})).then(function() {
return Promise.all(oldPostItemIDs.map(function(oldPostItemID) {
return userReceiptMetrics.child(userID).child('postItems').child(oldPostItemID).then(function(oldPostItem) {
var oldKey = oldPostItem.key
var newKey = oldKey.replace(oldProductID, newProductID)
var data = record.val()
updateObject['userReceiptMetrics/'+userID+'/postItems/'+newKey] = data;
updateObject['userReceiptMetrics/'+userID+'/postItems/'+oldKey] = null;
progress(38);
});
}))
}).catch(function(error) {
console.log('fudge louise');
});
}
});
Here is the console output:
App listening on port 8080
Press Ctrl+C to quit.
FIREBASE WARNING: Using an unspecified index. Consider adding ".indexOn": "_state" at /productUpdateQueue/tasks to your security rules for better performance
FIREBASE WARNING: Using an unspecified index. Consider adding ".indexOn": "_state" at /productUpdateQueue/tasks to your security rules for better performance
{ date: '2016-12-21 22:05:03',
itemID: 'Macys-EReceipts-MENS HOSIERY-Size(No size provided)-Color(No color provided)-786888403743',
postID: '-KZbmaThvxNmrvHwh_mc' }
{ date: '2016-12-21 22:05:03',
itemID: 'Macys-EReceipts-MENS HOSIERY-Size(No size provided)-Color(No color provided)-786888403743',
postID: '-KZbxAUcwzcP28C91EZA' }
FIREBASE WARNING: Using an unspecified index. Consider adding ".indexOn": "itemID" at /userReceiptMetrics/HeQST8hSkoPUmkBiVDR0tpSPo0x2/postItemIDs to your security rules for better performance
fudge louise

So it looks like the Promise.all() call failed because there is an empty object at the end of the list of objects. Here is the corrected code.
return userReceiptMetrics.child(userID).child('postItemIDs').orderByChild('itemID').equalTo(oldProductID).once('value', function(oldSnapshot) {
var oldPostItemIDs = [];
var metrics = oldSnapshot.val()
if (oldSnapshot.val() != null) {
return Promise.all(oldSnapshot.forEach(function(record) {
console.log(record.val());
var oldKey = record.key;
var newKey = oldKey.replace(oldProductID, newProductID);
var data = record.val();
oldPostItemIDs.push(oldKey);
data.itemID = newProductID;
updateObject['userReceiptMetrics/'+userID+'/postItemIDs/'+newKey] = data;
updateObject['userReceiptMetrics/'+userID+'/postItemIDs/'+oldKey] = null;
})).then(function() {
return oldPostItemIDs.map(function(oldPostItemID) {
return userReceiptMetrics.child(userID).child('postItems').child(oldPostItemID).then(function(oldPostItem) {
var oldKey = oldPostItem.key
var newKey = oldKey.replace(oldProductID, newProductID)
var data = record.val()
updateObject['userReceiptMetrics/'+userID+'/postItems/'+newKey] = data;
updateObject['userReceiptMetrics/'+userID+'/postItems/'+oldKey] = null;
progress(38);
});
})
}).catch(function(error) {
console.log('fudge louise');
});
}
});

Convert a text from text file to array with fs [node js]

I have a txt file contains:
{"date":"2013/06/26","statement":"insert","nombre":1}
{"date":"2013/06/26","statement":"insert","nombre":1}
{"date":"2013/06/26","statement":"select","nombre":4}
how I can convert the contents of the text file as array such as:
statement = [
{"date":"2013/06/26","statement":"insert","nombre":1},
{"date":"2013/06/26","statement":"insert","nombre":1},
{"date":"2013/06/26","statement":"select","nombre":4}, ];
I use the fs module node js. Thanks
Sorry
I will explain more detailed:
I have an array :
st = [
{"date":"2013/06/26","statement":"insert","nombre":1},
{"date":"2013/06/26","statement":"insert","nombre":5},
{"date":"2013/06/26","statement":"select","nombre":4},
];
if I use this code :
var arr = new LINQ(st)
.OrderBy(function(x) {return x.nombre;})
.Select(function(x) {return x.statement;})
.ToArray();
I get the result I want.
insert select insert
but the problem my data is in a text file.
any suggestion and thanks again.

There is no reason for not to do your file parser yourself. This will work on any size of a file:
var fs = require('fs');
var fileStream = fs.createReadStream('file.txt');
var data = "";
fileStream.on('readable', function() {
//this functions reads chunks of data and emits newLine event when \n is found
data += fileStream.read();
while( data.indexOf('\n') >= 0 ){
fileStream.emit('newLine', data.substring(0,data.indexOf('\n')));
data = data.substring(data.indexOf('\n')+1);
}
});
fileStream.on('end', function() {
//this functions sends to newLine event the last chunk of data and tells it
//that the file has ended
fileStream.emit('newLine', data , true);
});
var statement = [];
fileStream.on('newLine',function(line_of_text, end_of_file){
//this is the code where you handle each line
// line_of_text = string which contains one line
// end_of_file = true if the end of file has been reached
statement.push( JSON.parse(line_of_text) );
if(end_of_file){
console.dir(statement);
//here you have your statement object ready
}
});

If it's a small file, you might get away with something like this:
// specifying the encoding means you don't have to do `.toString()`
var arrayOfThings = fs.readFileSync("./file", "utf8").trim().split(/[\r\n]+/g).map(function(line) {
// this try/catch will make it so we just return null
// for any lines that don't parse successfully, instead
// of throwing an error.
try {
return JSON.parse(line);
} catch (e) {
return null;
}
// this .filter() removes anything that didn't parse correctly
}).filter(function(object) {
return !!object;
});
If it's larger, you might want to consider reading it in line-by-line using any one of the many modules on npm for consuming lines from a stream.
Wanna see how to do it with streams? Let's see how we do it with streams. This isn't a practical example, but it's fun anyway!
var stream = require("stream"),
fs = require("fs");
var LineReader = function LineReader(options) {
options = options || {};
options.objectMode = true;
stream.Transform.call(this, options);
this._buffer = "";
};
LineReader.prototype = Object.create(stream.Transform.prototype, {constructor: {value: LineReader}});
LineReader.prototype._transform = function _transform(input, encoding, done) {
if (Buffer.isBuffer(input)) {
input = input.toString("utf8");
}
this._buffer += input;
var lines = this._buffer.split(/[\r\n]+/);
this._buffer = lines.pop();
for (var i=0;i<lines.length;++i) {
this.push(lines[i]);
}
return done();
};
LineReader.prototype._flush = function _flush(done) {
if (this._buffer.length) {
this.push(this._buffer);
}
return done();
};
var JSONParser = function JSONParser(options) {
options = options || {};
options.objectMode = true;
stream.Transform.call(this, options);
};
JSONParser.prototype = Object.create(stream.Transform.prototype, {constructor: {value: JSONParser}});
JSONParser.prototype._transform = function _transform(input, encoding, done) {
try {
input = JSON.parse(input);
} catch (e) {
return done(e);
}
this.push(input);
return done();
};
var Collector = function Collector(options) {
options = options || {};
options.objectMode = true;
stream.Transform.call(this, options);
this._entries = [];
};
Collector.prototype = Object.create(stream.Transform.prototype, {constructor: {value: Collector}});
Collector.prototype._transform = function _transform(input, encoding, done) {
this._entries.push(input);
return done();
};
Collector.prototype._flush = function _flush(done) {
this.push(this._entries);
return done();
};
fs.createReadStream("./file").pipe(new LineReader()).pipe(new JSONParser()).pipe(new Collector()).on("readable", function() {
var results = this.read();
console.log(results);
});

fs.readFileSync("myfile.txt").toString().split(/[\r\n]/)
This gets your each line as a string
You can then use UnderscoreJS or your own for loop to apply the JSON.parse("your json string") method to each element of the array.

var arr = fs.readFileSync('mytxtfile', 'utf-8').split('\n')
I think this is the simplest way of creating an array from your text file