I have a list, which contains items such as this:
[{name:...}, {name:...}], ...
I would like to extract only those elements, where name matches to any in a set of regular expressions.
I was able to do it like so:
const cards = yield ... //Network request to get my list of items
const matchers = [/^Remaining Space:/, /^Remaining Weight:/, /^Gross:/];
const propTester = (prop, pred) => R.pipe(R.prop(prop), R.test(pred));
const extractors = R.ap([propTester('name')], matchers);
const [ spaceCard, weightCard, grossCard ] =
R.ap(R.ap([R.find], extractors), [cards]);
Is there any way to simplify that?
Here's one possibility:
const matchers = [/^Remaining Space:/, /^Remaining Weight:/, /^Gross:/];
const testers = R.map(pred => R.pipe(R.prop('name'), R.test(pred)), matchers);
const extractors = R.map(R.find, testers)
const [ spaceCard, weightCard, grossCard ] = R.juxt(extractors)(cards);
It assumes that 'name' is fixed and you don't need to be able to change it dynamically. If you do, it would be slightly more work. The main point is the use of R.juxt, which "applies a list of functions to a list of values."
If we tried really hard, we could probably make testers points-free as well, but threading all that through the whole thing to make a single function from matchers and cards to your results, while possible, would likely read to less readable code.
You can see this in action on the Ramda REPL.
Related
Lets say I have this array
const urlList = ["/user/profile", "/user/edit", "/verify/device"];
const isContainUrl = fruits.includes(window.location.pathname);
That is fine if pathname is static like above, what if I have url like /verify/device/{device-id} , I want isContainUrl to be true as well for partial match. But since I am comparing longer string to the shorter one, so I cant simple use indexOf.
May be anyone has any idea to do it?
It is possible to use some() and check both edge cases:
const urlList = ["/user/profile", "/user/edit", "/verify/device"];
const veryLongString = '/verify/device/1';
const isContainUrl = urlList.some(s => s.includes(veryLongString)
|| veryLongString.includes(s));
console.log(isContainUrl)
You need to parse url according to custom rules, or do some regular matching work.
Refer to path-to-regexp.
So here is a description of the problem that I've been talked to solve:
We need some logic that extracts the variable parts of a url into a hash. The keys
of the extract hash will be the "names" of the variable parts of a url, and the
values of the hash will be the values. We will be supplied with:
A url format string, which describes the format of a url. A url format string
can contain constant parts and variable parts, in any order, where "parts"
of a url are separated with "/". All variable parts begin with a colon. Here is
an example of such a url format string:
'/:version/api/:collection/:id'
A particular url instance that is guaranteed to have the format given by
the url format string. It may also contain url parameters. For example,
given the example url format string above, the url instance might be:
'/6/api/listings/3?sort=desc&limit=10'
Given this example url format string and url instance, the hash we want that
maps all the variable parts of the url instance to their values would look like this:
{
version: 6,
collection: 'listings',
id: 3,
sort: 'desc',
limit: 10
}
So I technically have a semi-working solution to this but, my questions are:
Am I understanding the task correctly? I'm not sure if I'm supposed to be dealing with two inputs (URL format string and URL instance) or if I'm just supposed to be working with one URL as a whole. (my solution takes two separate inputs)
In my solution, I keep reusing the split() method to chunk the array/s down and it feels a little repetitive. Is there a better way to do this?
If anyone can help me understand this challenge better and/or help me clean up my solution, it would be greatly appreciated!
Here is my JS:
const obj = {};
function parseUrl(str1, str2) {
const keyArr = [];
const valArr = [];
const splitStr1 = str1.split("/");
const splitStr2 = str2.split("?");
let val1 = splitStr2[0].split("/");
let val2 = splitStr2[1].split("&");
splitStr1.forEach((i) => {
keyArr.push(i);
});
val1.forEach((i) => {
valArr.push(i);
});
val2.forEach((i) => {
keyArr.push(i.split("=")[0]);
valArr.push(i.split("=")[1]);
});
for (let i = 0; i < keyArr.length; i++) {
if (keyArr[i] !== "" && valArr[i] !== "") {
obj[keyArr[i]] = valArr[i];
}
}
return obj;
};
console.log(parseUrl('/:version/api/:collection/:id', '/6/api/listings/3?sort=desc&limit=10'));
And here is a link to my codepen so you can see my output in the console:
https://codepen.io/TOOTCODER/pen/yLabpBo?editors=0012
Am I understanding the task correctly? I'm not sure if I'm supposed to
be dealing with two inputs (URL format string and URL instance) or if
I'm just supposed to be working with one URL as a whole. (my solution
takes two separate inputs)
Yes, your understanding of the problem seems correct to me. What this task seems to be asking you to do is implement a route parameter and a query string parser. These often come up when you want to extract data from part of the URL on the server-side (although you don't usually need to implement this logic your self). Do keep in mind though, you only want to get the path parameters if they have a : in front of them (currently you're retrieving all values for all), not all parameters (eg: api in your answer should be excluded from the object (ie: hash)).
In my solution, I keep reusing the split() method to chunk the array/s
down and it feels a little repetitive. Is there a better way to do
this?
The number of .split() methods that you have may seem like a lot, but each of them is serving its own purpose of extracting the data required. You can, however, change your code to make use of other array methods such as .map(), .filter() etc. to cut your code down a little. The below code also considers the case when no query string (ie: ?key=value) is provided:
function parseQuery(queryString) {
return queryString.split("&").map(qParam => qParam.split("="));
}
function parseUrl(str1, str2) {
const keys = str1.split("/")
.map((key, idx) => [key.replace(":", ""), idx, key.charAt(0) === ":"])
.filter(([,,keep]) => keep);
const [path, query = ""] = str2.split("?");
const pathParts = path.split("/");
const entries = keys.map(([key, idx]) => [key, pathParts[idx]]);
return Object.fromEntries(query ? [...entries, ...parseQuery(query)] : entries);
}
console.log(parseUrl('/:version/api/:collection/:id', '/6/api/listings/3?sort=desc&limit=10'));
It would be even better if you don't have to re-invent the wheel, and instead make use of the URL constructor, which will allow you to extract the required information from your URLs more easily, such as the search parameters, this, however, requires that both strings are valid URLs:
function parseUrl(str1, str2) {
const {pathname, searchParams} = new URL(str2);
const keys = new URL(str1).pathname.split("/")
.map((key, idx) => [key.replace(":", ""), idx, key.startsWith(":")])
.filter(([,,keep]) => keep);
const pathParts = pathname.split("/");
const entries = keys.map(([key, idx]) => [key, pathParts[idx]]);
return Object.fromEntries([...entries, ...searchParams]);
}
console.log(parseUrl('https://www.example.com/:version/api/:collection/:id', 'https://www.example.com/6/api/listings/3?sort=desc&limit=10'));
Above, we still need to write our own custom logic to obtain the URL parameters, however, we don't need to write any logic to extract the query string data as this is done for us by using URLSearchParams. We're also able to lower the number of .split()s used as we can obtain use the URL constructor to give us an object with a parsed URL already. If you end up using a library (such as express), you will get the above functionality out-of-the-box.
var product_id = "14728";
console.log(product_id.includes("14782,12434,3143")); // this return false
Example.
I just want to check that my product_id is within those other articles ids string
Two reasons:
You have it backwards. You are asking if "14728" includes "14782,12434,3143" (which it doesn't, the latter is too long to be included in the former for a start), not the other way around
"14782,12434,3143" doesn't include "14728" anyway
Your approach is also broken. "14782,12434,3143" includes "314". Presumably you want to only match complete numbers in the comma-separated list. You need to use Array.prototype.includes, not String.prototype.includes.
const myData = ["14782", "12434", "3143"];
const mySearch = "14728"; // Not in the array
const myOtherSearch = "12434"; // In the array
console.log(myData.includes(mySearch));
console.log(myData.includes(myOtherSearch));
I may or may not get in 2 differently formatted bits of data.
They both need to be stripped of characters in different ways. Please excuse the variable names, I will make them better once I have this working.
const cut = flatten.map(obj => {
return obj.file.replace("0:/", "");
});
const removeDots = flatten.map(obj => {
return obj.file.replace("../../uploads/", "");
})
I then need to push the arrays into my mongo database.
let data;
for (const loop of cut) {
data = { name: loop };
product.images.push(data);
}
let moreData;
for (const looptwo of removeDots) {
moreData = {name: looptwo};
product.images.push(moreData);
}
I wanted to know if there is a way to either join them or do an if/else because the result of this is that if I have 2 records, it ends up duplicating and I get 4 records instead of 2. Also, 2 of the records are incorrectly formatted ie: the "0:/ is still present instead of being stripped away.
Ideally I would like have a check that if 0:/ is present, remove it, if ../../uploads/ is present or if both are present, remove both. And then create an array from that to push.
You can do your 2 replace on the same map :
const processed = flatten.map(obj => {
return obj.file.replace("0:/", "").replace("../../uploads/", "");
});
Since you know the possible patterns, you can create a regex and use it to replace any occurrences.
const regex = /(0:\/|(\.\.\/)+uploads\/)/g
const processed = flatten.map(obj => obj.file.replace(regex, ''));
You can verify here
Note, regex is a pattern based approach. So it has pros and cons.
Pro:
You can have any number of folder nesting. Using string ../../uploads/ will restrict you with 2 folder structure only.
You can achieve transformation in 1 operation and code looks clean.
Cons:
Regex can be hard to understand and can reduce readability of code a bit. (Opinionated)
If you have pattern like .../../uploads/bla, this will be parsed to .bla.
Since you ask also about a possible way of joining two arrays, I'll give you couple of solutions (with and w/o joining).
You can either chain .replace on the elements of the array, or you can concat the two arrays in your solution. So, either:
const filtered = flatten.map(obj => {
return obj.file.replace('0:/', '').replace('../../uploads/', '');
});
Or (joining the arrays):
// your two .map calls go here
const joinedArray = cut.concat(removeDots);
I have spent hours, close to 8 hours none stop on this, I am trying to use jQuery/JS to create two arrays, one which is dynamic as it is loading a chat script and will be split by whitespace in to an array, for example:
String: Hello my name is Peter
Converted to (message) array: ['hello','my','name','is','peter'];
I have a set array to look out for specific words, in this example let us use:
(find array) ['hello','peter'] however, this array is going to contain up to 20 elements and I need to ensure it searches the message array efficiently, please help.
I can help you with that.
var arrayOfWords = $(".echat-shared-chat-message-body").last().text().split(" ");
That code is actually working! i went to an open chat in this website so I can tested.
So just replace the word REPLACE with your DOM object :)
var arrayOfWords = $("REPLACE").last().text().split(" ");
If I understood well, you're asking to filter an array of string (from an incoming string) given a second array.
In your described case you'll certainly not have to worry about efficiency, really. Unless your incoming message is allowed to be very very big.
Given that, there is a dozen of options, I think this is the most succinct:
const whitelist = [
'hello',
'peter'
]
const message = 'hello my name is Peter'.split(' ')
const found = message.filter(function(word) {
return whitelist.indexOf(word) > -1
}
You can treat invariant case:
const whitelistLower = whitelist.toLowerCase()
const foundInvariantCase = message.filter(function(word) {
return whitelist.indexOf(word.toLowerCase()) > -1
}
Or use ESS Set:
const whitelistSet = new Set(whitelist)
const found = message.filter(function(word) {
return whitelistSet.has(word)
}