Hi JS-heroes! Finally done with this new article! Let's go ahead ✨
1. Generate a list with random numbers
We need A LOT of fake data, for different reasons. So here's a way to do that gently.
Array.from({ length: 1000 }, Math.random)
// [ 0.6163093133259432, 0.8877401276499153, 0.4094354756035987, ...] - 1000 items
2. Generate a list with numbers
Yep, just one more trick to generate a list with numbers.
Array.from({ length: 1000 }, (v, i) => i)
// [0, 1, 2, 3, 4, 5, 6....999]
1-2 edited. Thanks to Andrew Courtice
3. Convert RGB → HEX
Convert your RGB to HEX without any libs!
const rgb2hex = ([r, g, b]) =>
'#' + ((1 << 24) + (r << 16) + (g << 8) + b).toString(16).substr(1);
rgb2hex([76, 11, 181]);
// #4c0bb5
4. Convert HEX → RGB
What's about convert it back?! Here's a nice way to implement that.
const hex2rgb = hex =>
[1, 3, 5].map((h) => parseInt(hex.substring(h, h + 2), 16));
hex2rgb("#4c0bb5");
// [76, 11, 181]
5. Odd or Even
Another yet odd/even checking.
const value = 232;
if (value & 1) console.log("odd");
else console.log("even");
// even
6. Check valid URL
I guess most of you use this way to validate URL, but anyway. Let's share it
const isValidURL = (url) => {
try {
new URL(url);
return true;
} catch (error) {
return false;
}
};
isValidURL("https://dev.to");
// true
isValidURL("https//invalidto");
// false
7. N something ago
Sometimes you need something to print a date to 6 minute(s) ago
, but don't want to import monster-size libs. Here's a small snippet that does it, easily modify it as you wish and go ahead.
const fromAgo = (date) => {
const ms = Date.now() - date.getTime();
const seconds = Math.round(ms / 1000);
const minutes = Math.round(ms / 60000);
const hours = Math.round(ms / 3600000);
const days = Math.round(ms / 86400000);
const months = Math.round(ms / 2592000000);
const years = Math.round(ms / 31104000000);
switch (true) {
case seconds < 60:
return `${seconds} second(s) ago"`;
case minutes < 60:
return `${minutes} minute(s) ago"`;
case hours < 24:
return `${hours} hour(s) ago"`;
case days < 30:
return `${days} day(s) ago`;
case months < 12:
return `${months} month(s) ago`;
default:
return `${years} year(s) ago`;
}
};
const createdAt = new Date(2021, 0, 5);
fromAgo(createdAt); // 14 day(s) ago;
8. Generate path with params
We work a lot with routes/paths and we always need to manipulate them. When we need to generate a path w/ params to push browser there, generatePath helps us!
const generatePath = (path, obj) =>
path.replace(/(\:[a-z]+)/g, (v) => obj[v.substr(1)]);
const route = "/app/:page/:id";
generatePath(route, {
page: "products",
id: 85,
});
// /app/products/123
9. Get params from path
Yes! Now we need to get our params back. Also, you can pass serializer to parse your data gently.
const getPathParams = (path, pathMap, serializer) => {
path = path.split("/");
pathMap = pathMap.split("/");
return pathMap.reduce((acc, crr, i) => {
if (crr[0] === ":") {
const param = crr.substr(1);
acc[param] = serializer && serializer[param]
? serializer[param](path[i])
: path[i];
}
return acc;
}, {});
};
getPathParams("/app/products/123", "/app/:page/:id");
// { page: 'products', id: '123' }
getPathParams("/items/2/id/8583212", "/items/:category/id/:id", {
category: v => ['Car', 'Mobile', 'Home'][v],
id: v => +v
});
// { category: 'Home', id: 8583212 }
10. Generate path with query string
Of course, we work with paths and we need to generate path with query too.
const generatePathQuery = (path, obj) =>
path +
Object.entries(obj)
.reduce((total, [k, v]) => (total += `${k}=${encodeURIComponent(v)}&`), "?")
.slice(0, -1);
generatePathQuery("/user", { name: "Orkhan", age: 30 });
// "/user?name=Orkhan&age=30"
11. Get params from query string
Now it's a time to get params from query string.
const getQueryParams = url =>
url.match(/([^?=&]+)(=([^&]*))/g).reduce((total, crr) => {
const [key, value] = crr.split("=");
total[key] = value;
return total;
}, {});
getQueryParams("/user?name=Orkhan&age=30");
// { name: 'Orkhan', age: '30' }
Conclusion
Try to understand how everything works and keep your code nice/clean.
Take your JS-hero's skills and save the world! ✨🦸♂️ ✨
Save and contribute tips/tricks on github code-like
Top comments (21)
One that I love is this:
The or operator works the same as an elvis operator.
This is useful if you want to display a default value when you can't get data from an api or if some data is null for a key.
This can be chained with objects
Love this one too, it's also useful to prevent errors when destructuring something that could be undefined:
This can prevent errors such as "Cannot read foo of undefined".
With ES2021 we have
||=
:)Which makes the syntax even cooler
I made a video about new features here:
youtu.be/hxmFYToenxE
True but not fully supported yet
With the right babelJS version it is ;)
And then you're bringing big pieces of extra code for not much 😉 good way to slow websites.
I would say that developer convenience is more than a lot. Also, few bytes of code for polyfill, definitely will not slow down the website.
I tend to think of client first. UX is more important than writing one word less. for a developer. between users having slow internet speeds, limited networks and not the greatest machines bringing one poly-fill here and there vs zero can make a huge difference. If you are making something just for you or limited public then why not but the difference in code between the statement I used vs using
||=
is not that big that it would justify using a poly-fill on my end. If we were talking about a promise polyfill for example that would be a different matter.But in the end everyone codes differently. So whatever suits your coding style then use it.
Great article!
It's worth noting that the first 2 examples can be written ever so slightly shorter using
Array.from
as theArray.from
method supports a mapping function as it's second argument.Here's the first example using
Array.from
:And the second example:
You're right! This way is slightly shorter! I'll replace mine with them
Thank you mate!
Here is what I use
Array from for the win I had an issue with array fill hahaha
How Array.fill can break arrays!
Médéric Burlet ・ Oct 7 '20 ・ 2 min read
In the case of no. 5: I would always chose readability over bitwise trickery, when not absolutely necessary. So instead of bitwise AND, just use modulo;
Hey just a small improvement to N something ago example to show/hide plural.
This will not work for months with 31 days.
It's a just simple version for that formatter. That's why it shows average time.
But it's okay with 31 days. If it's more than 30 days then 1 month;
example
You can also replace
Date.now()
with your own date to check withdate.getTime()
Thanks for your work.
Array.from() is amazing! I always used new Array(10). Thanks :)
Great article :D
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