Develop Reference

Why is my code behaving like I have duplicate keys in a dictionary despite using unique strings? Javascript / Appscript

I am trying to loop through a dictionary of customers and save energy usage data, but for some customers when I try to change the values in their usage dictionary it will also change a completely different customer's value. I have a nested dictionary with customer utility information, the top-level key being a unique internal ID.
I stripped my code down to a single loop, looping through the top-level keys and setting the same month's usage for all customers in the dictionary to be the value of the iterator. After that, as shown in the code sample below, I log the values for three customers. After that, I increment only one of those customer's usage, and log the values again. The console shows that two over the customer's have dictionaries that are tied together somehow, but I can't figure out why or how to solve this. I can't discern any pattern in the keys of the linked customers, either.
Structure of the nested dictionary:
CustDict =
{"N0100000XXXXXX" =
{"name" = "XXXX"},
{"address" = "XXXX"},
{"meter_read_dates" =
{"2021-05-13" =
{"usage" = "XXXX"}
}
}
}
Stripped down code I used to demonstrate what is happening as simply as possible (real ID values):
Logger.log(custDict["N01000009700816"]["meter_read_dates"]["2021-05-13"]["usage"])
Logger.log(custDict["N01000000419887"]["meter_read_dates"]["2021-05-13"]["usage"])
Logger.log(custDict["N01000012580668"]["meter_read_dates"]["2021-05-13"]["usage"])
custDict["N01000009700816"]["meter_read_dates"]["2021-05-13"]["usage"] =
custDict["N01000009700816"]["meter_read_dates"]["2021-05-13"]["usage"] + 1
Logger.log(custDict["N01000009700816"]["meter_read_dates"]["2021-05-13"]["usage"])
Logger.log(custDict["N01000000419887"]["meter_read_dates"]["2021-05-13"]["usage"])
Logger.log(custDict["N01000012580668"]["meter_read_dates"]["2021-05-13"]["usage"])
Console Output:
11:54:56 AM Info 346.0
11:54:56 AM Info 346.0
11:54:56 AM Info 322.0
11:54:56 AM Info 347.0
11:54:56 AM Info 347.0
11:54:56 AM Info 322.0
Code used to create the CustDict dictionary:
stmtCR = conn.prepareStatement('SELECT cust_id, utility_account, cycle_id, read_cycle FROM customers')
results = stmtCR.executeQuery()
resultsMetaData = results.getMetaData()
numCols = resultsMetaData.getColumnCount();
results.last();
numRows = results.getRow();
i = 0
results.first()
var custDict = {}
while (i < numRows)
{
custDict[results.getString(1)] = {}
custDict[results.getString(1)]["id"] = results.getString(1)
custDict[results.getString(1)]["utility_account"] = results.getString(2)
custDict[results.getString(1)]["cycle_id"] = results.getString(3)
custDict[results.getString(1)]["read_cycle"] = results.getString(4)
results.next()
i++;
}
for (i = 0; i < Object.keys(custDict).length; i++)
{
tempCust = custDict[Object.keys(custDict)[i]]
tempCycleId = tempCust["cycle_id"]
tempReadCycle = tempCust["read_cycle"]
tempCust["meter_read_dates"] = cycleIdShdDict[tempCycleId][tempReadCycle]
custDict[Object.keys(custDict)[i]] = tempCust
}
cycleIdShdDict is a seperate dictionary that contains a set of dates associated with each cycle_id and read_cycle

I suspect the problem is that Object.keys(custDict) is returning the keys in a different order at different places in the for loop. So you're getting the object from one key, and then assigning it to a different key.
There's no need to assign back to custDict[Object.keys(custDict)[i]] since you're modifying the object in place, not a copy.
But instead of looping through the keys, loop through the values and modify them.
Object.values(custDict).forEach(tempCust => {
let tempCycleId = tempCust["cycle_id"];
let tempReadCycle = tempCust["read_cycle"];
tempCust["meter_read_dates"] = cycleIdShdDict[tempCycleId][tempReadCycle];
});

JS map to translate values back and forth

I'm trying to figure out the best way to approach mapping values back and forward as a sort of translation process. The use case is having to process a non SEO friendly attribute code into a nicer format and display that on the frontend, but i also need to be able to process the nice attribute label back into original code so i can use that in my script. In the following example, i'd want to be able to look up myMap to check if a string value exists in the object, and if it does, pull out its corresponding label.
var myString = 'color_attr_code'; // Want to be able to extract 'color' from the map
var myAltString = 'color'; // Want to be able to extract 'color_attr_code'
var myMap = {
'color_attr_code': 'color'
}
Thanks for any help.

You're on the right track, though in modern environments you might use a Map rather than an object, or at least create the object without a prototype so there aren't false matches on toString or valueOf or other things the default object prototype provides.
You'd have two maps, one going each direction, probably best derived from the same source data:
const mappings = [
["color_attr_code", "color"],
["blah_attr_code", "blah"],
// ...
];
const attrToLabel = new Map(mappings);
const labelToAttr = new Map(mappings.map(([key, value]) => [value, key]));
Then you use attrToLabel.get("color_attr_code") to get the corresponding label, and labelToAttr.get("color") to get the corresponding code.
Live Example:
const mappings = [
["color_attr_code", "color"],
["blah_attr_code", "blah"],
// ...
];
const attrToLabel = new Map(mappings);
const labelToAttr = new Map(mappings.map(([key, value]) => [value, key]));
console.log(`Label for "color_attr_code": ${attrToLabel.get("color_attr_code")}`);
console.log(`Code for "color": ${labelToAttr.get("color")}`);
Or in ES5 (although really, in today's world, there's no reason to write ES5 manually — write modern code and transpile with Babel or similar) and objects:
var mappings = [
["color_attr_code", "color"],
["blah_attr_code", "blah"],
// ...
];
var attrToLabel = Object.create(null);
var labelToAttr = Object.create(null);
mappings.forEach(function(mapping) {
var code = mapping[0], label = mapping[1];
attrToLabel[code] = label;
labelToAttr[label] = code;
});
Then you use attrToLabel["color_attr_code"] to get the corresponding label, and labelToAttr["color"] to get the corresponding code.
Of course, all of this assumes there are always just 1:1 mappings, that there aren't (for instance) two codes that both map to the same label.

Javascript ForEach on Array of Arrays

I am looping through a collection of blog posts to firstly push the username and ID of the blog author to a new array of arrays, and then secondly, count the number of blogs from each author. The code below achieves this; however, in the new array, the username and author ID are no longer separate items in the array, but seem to be concatenated into a single string. I need to retain them as separate items as I need to use both separately; how can I amend the result to achieve this?
var countAuthors = [];
blogAuthors = await Blog.find().populate('authors');
blogAuthors.forEach(function(blogAuthor){
countAuthors.push([blogAuthor.author.username, blogAuthor.author.id]);
})
console.log(countAuthors);
// Outputs as separate array items, as expected:
// [ 'author1', 5d7eed028c298b424b3fb5f1 ],
// [ 'author2', 5dd8aa254d74b30017dbfdd3 ],
var result = {};
countAuthors.forEach(function(x) {
result[x] = (result[x] || 0) + 1;
});
console.log(result);
// Username and author ID become a single string and cannot be accessed as separate array items
// 'author1,5d7eed028c298b424b3fb5f1': 15,
// 'author2,5dd8aa254d74b30017dbfdd3': 2,
Update:
Maybe I can explain a bit further WHY on what to do this. What I am aiming for is a table which displays the blog author's name alongside the number of blogs they have written. However, I also want the author name to link to their profile page, which requires the blogAuthor.author.id to do so. Hence, I need to still be able to access the author username and ID separately after executing the count. Thanks

You could use String.split().
For example:
let result = 'author1,5d7eed028c298b424b3fb5f1'.split(',')
would set result to:
['author1' , '5d7eed028c298b424b3fb5f1']
You can then access them individually like:
result[1] //'5d7eed028c298b424b3fb5f1'

Your issue is that you weren't splitting the x up in the foreach callback, and so the whole array was being converted to a string and being used as the key when inserting into the results object.
You can use array destructuring to split the author name and blog id, and use them to optionally adding a new entry to the result object, and then update that result.
countAuthors = [
['author1', 'bookId1'],
['author2', 'bookId2'],
['author1', 'bookId3'],
['author1', 'bookId4'],
['author2', 'bookId5']
]
var result = {};
countAuthors.forEach(([author, id]) => {
if (result[author] === undefined) {
result[author] = {count: 0, blogIds: []};
}
result[author].count += 1;
result[author].blogIds.push(id);
});
console.log(result);

How can I parse a .frd file with Javascript?

A .frd file is a type of multi-column numeric data table used for storing information about the frequency response of speakers. A .frd file looks something like this when opened in a text editor:
2210.4492 89.1 -157.7
2216.3086 88.99 -157.7
2222.168 88.88 -157.6
2228.0273 88.77 -157.4
Using javascript, is there a way that I can parse this data in order to return each column separately?
For example, from the .frd file above, I would need to return the values like so:
var column1 = [2210.4492, 2216.3086, 2222.168, 2228.0273];
var column2 = [89.1, 88.99, 88.88, 88.77];
var column3 = [-157.7, -157.7, -157.6, -157.4];
I'm not exactly sure where to begin in trying to achieve this, so any step in the right direction would be helpful!

I found the following description of the FRD file format and I will follow it.
Let's assume that the content of your .frd file is in the variable called content (the following example is for Node.js):
const fs = require('fs');
const content = fs.readFileSync('./input.frd').toString();
Now if content has your FRD data, it means it's a set of lines, each line contains exactly three numbers: a frequency (Hz), a level (dB), and a phase (degrees). To split your content into lines, we can just literally split it:
const lines = content.split(/\r?\n/);
(normally, splitting just by '\n' would've worked, but let's explicitly support Windows-style line breaks \r\n just in case. The /\r?\n/ is a regular expression that says "maybe \r, then \n")
To parse each line into three numbers, we can do this:
const values = line.split(/\s+/);
If the file can contain empty lines, it may make sense to double check that the line has exactly three values:
if (values.length !== 3) {
// skip this line
}
Given that we have three values in values, as strings, we can assign the corresponding variables:
const [frequency, level, phase] = values.map(value => Number(value));
(.map converts all the values in values from strings to Number - let's do this to make sure we store the correct type).
Now putting all those pieces together:
const fs = require('fs');
const content = fs.readFileSync('./input.frd').toString();
const frequencies = [];
const levels = [];
const phases = [];
const lines = content.split(/\r?\n/);
for (const line of lines) {
const values = line.split(/\s+/);
if (values.length !== 3) {
continue;
}
const [frequency, level, phase] = values.map(value => Number(value));
frequencies.push(frequency);
levels.push(level);
phases.push(phase);
}
console.log(frequencies);
console.log(levels);
console.log(phases);
The main code (the one that works with content) will also work in browser, not just in Node.js, if you need that.
This code can be written in a tons of different ways, but I tried to make it easier to explain so did something very straightforward.
To use it in Node.js (if your JavaScript file is called index.js):
$ cat input.frd
2210.4492 89.1 -157.7
2216.3086 88.99 -157.7
2222.168 88.88 -157.6
2228.0273 88.77 -157.4
$ node index.js
[ 2210.4492, 2216.3086, 2222.168, 2228.0273 ]
[ 89.1, 88.99, 88.88, 88.77 ]
[ -157.7, -157.7, -157.6, -157.4 ]

How can I use underscore in name of dynamic object variable

Website that I'm making is in two different languages each data is saved in mongodb with prefix _nl or _en
With a url I need to be able to set up language like that:
http://localhost/en/This-Is-English-Head/This-Is-English-Sub
My code look like that:
var headPage = req.params.headPage;
var subPage = req.params.subPage;
var slug = 'name';
var slugSub = 'subPages.slug_en';
var myObject = {};
myObject[slugSub] = subPage;
myObject[slug] = headPage;
console.log(myObject);
Site.find(myObject,
function (err, pages) {
var Pages = {};
pages.forEach(function (page) {
Pages[page._id] = page;
});
console.log(Pages);
});
After console.log it I get following:
{ 'subPages.slug_en': 'This-Is-English-Sub',
name: 'This-Is-English-Head' }
Is you can see objectname subPages.slug_en is seen as a String insteed of object name..
I know that javascript does not support underscores(I guess?) but I'm still looking for a fix, otherwise i'll be forced to change all underscores in my db to different character...
Edit:
The final result of console.log need to be:
{ subPages.slug_en: 'This-Is-English-Sub',
name: 'This-Is-English-Head' }
Insteed of :
{ 'subPages.slug_en': 'This-Is-English-Sub',
name: 'This-Is-English-Head' }
Otherwise it does not work

The reason you are seeing 'subPages.slug_en' (with string quotes) is because of the . in the object key, not the underscore.
Underscores are definitely supported in object keys without quoting.
Using subPages.slug_en (without string quotes) would require you to have an object as follows:
{ subPages: {slug_en: 'This-Is-English-Sub'},
name: 'This-Is-English-Head' }
Which you could set with the following:
myObject['subPages']['slug_en'] = subPage;
Or simply:
myObject.subPages.slug_en = subPage;