DEV Community

Cover image for 7 Shorthand Optimization Tricks every JavaScript Developer Should Know 😎
Tapajyoti Bose
Tapajyoti Bose

Posted on • Edited on

7 Shorthand Optimization Tricks every JavaScript Developer Should Know 😎

Every language has its own quirks and JavaScript, the most used programming language, is no exception. This article will cover a plethora of JavaScript Shorthand Optimization tricks that can help you write better code, and also make sure this is NOT your reaction when you encounter them:

confused-face

1. Multiple string checks

Often you might need to check if a string is equal to one of the multiple values, and can become tiring extremely quickly. Luckily, JavaScript has a built-in method to help you with this.

// Long-hand
const isVowel = (letter) => {
  if (
    letter === "a" ||
    letter === "e" ||
    letter === "i" ||
    letter === "o" ||
    letter === "u"
  ) {
    return true;
  }
  return false;
};

// Short-hand
const isVowel = (letter) =>
  ["a", "e", "i", "o", "u"].includes(letter);
Enter fullscreen mode Exit fullscreen mode

2. For-of and For-in loops

For-of and For-in loops are a great way to iterate over an array or object without having to manually keep track of the index of the keys of the object.

For-of

const arr = [1, 2, 3, 4, 5];

// Long-hand
for (let i = 0; i < arr.length; i++) {
  const element = arr[i];
  // ...
}

// Short-hand
for (const element of arr) {
  // ...
}
Enter fullscreen mode Exit fullscreen mode

For-in

const obj = {
  a: 1,
  b: 2,
  c: 3,
};

// Long-hand
const keys = Object.keys(obj);
for (let i = 0; i < keys.length; i++) {
  const key = keys[i];
  const value = obj[key];
  // ...
}

// Short-hand
for (const key in obj) {
  const value = obj[key];
  // ...
}
Enter fullscreen mode Exit fullscreen mode

3. Falsey checks

If you want to check if a variable is null, undefined, 0, false, NaN, or an empty string, you can use the Logical Not (!) operator to check for all of them at once, without having to write multiple conditions. This makes it easy to check if a variable contains valid data.

// Long-hand
const isFalsey = (value) => {
  if (
    value === null ||
    value === undefined ||
    value === 0 ||
    value === false ||
    value === NaN ||
    value === ""
  ) {
    return true;
  }
  return false;
};

// Short-hand
const isFalsey = (value) => !value;
Enter fullscreen mode Exit fullscreen mode

4. Ternary operator

As a JavaScript developer, you must have encountered the ternary operator. It is a great way to write concise if-else statements. However, you can also use it to write concise code and even chain them to check for multiple conditions.

// Long-hand
let info;
if (value < minValue) {
  info = "Value is too small";
} else if (value > maxValue) {
  info = "Value is too large";
} else {
  info = "Value is in range";
}

// Short-hand
const info =
  value < minValue
    ? "Value is too small"
    : value > maxValue ? "Value is too large" : "Value is in range";
Enter fullscreen mode Exit fullscreen mode

5. Function calls

With the help of the ternary operator, you can also determine which function to call based on conditions.

IMPORTANT SIDE-NOTE: The call signature of the functions must be the same, else you risk running into an errors

function f1() {
  // ...
}
function f2() {
  // ...
}

// Long-hand
if (condition) {
  f1();
} else {
  f2();
}

// Short-hand
(condition ? f1 : f2)();
Enter fullscreen mode Exit fullscreen mode

6. Switch shorthand

Long switch cases can often be optimized by using an object with the keys as the switches and the values as the return values.

const dayNumber = new Date().getDay();

// Long-hand
let day;
switch (dayNumber) {
  case 0:
    day = "Sunday";
    break;
  case 1:
    day = "Monday";
    break;
  case 2:
    day = "Tuesday";
    break;
  case 3:
    day = "Wednesday";
    break;
  case 4:
    day = "Thursday";
    break;
  case 5:
    day = "Friday";
    break;
  case 6:
    day = "Saturday";
}

// Short-hand
const days = {
  0: "Sunday",
  1: "Monday",
  2: "Tuesday",
  3: "Wednesday",
  4: "Thursday",
  5: "Friday",
  6: "Saturday",
};
const day = days[dayNumber];
Enter fullscreen mode Exit fullscreen mode

7. Fallback values

The || operator can set a fallback value for a variable.

// Long-hand
let name;
if (user?.name) {
  name = user.name;
} else {
  name = "Anonymous";
}

// Short-hand
const name = user?.name || "Anonymous";
Enter fullscreen mode Exit fullscreen mode

That's all folks! πŸŽ‰

Finding personal finance too intimidating? Checkout my Instagram to become a Dollar Ninja

Thanks for reading

Need a Top Rated Front-End Development Freelancer to chop away your development woes? Contact me on Upwork

Want to see what I am working on? Check out my Personal Website and GitHub

Want to connect? Reach out to me on LinkedIn

I am a Digital Nomad and occasionally travel. Follow me on Instagram to check out what I am up to.

Follow my blogs for bi-weekly new tidbits on Dev

FAQ

These are a few commonly asked questions I get. So, I hope this FAQ section solves your issues.

  1. I am a beginner, how should I learn Front-End Web Dev?
    Look into the following articles:

    1. Front End Development Roadmap
    2. Front End Project Ideas
  2. Would you mentor me?

    Sorry, I am already under a lot of workload and would not have the time to mentor anyone.

Top comments (54)

Collapse
 
exodes profile image
Exo Des

I think the the fallback values need some correction. Using logical OR || doesn’t give you the value you want if the value is [] or 0. The better solution would be using the nullish coalescence ?? where if only use the fallback values when the defined value is null or undefined.

Collapse
 
the_riz profile image
Rich Winter

☝️

Collapse
 
seagull29 profile image
Erian

☝️

Thread Thread
 
0x04 profile image
Oliver KΓΌhn

☝️

Thread Thread
 
birkankervan profile image
Emre Birkan Kervan

☝️

Thread Thread
 
pogpog profile image
pogpog

☝️

Thread Thread
 
gabrandalisse profile image
Gabriel Andres

☝️

Collapse
 
moopet profile image
Ben Sinclair

In point 1, everything's fine, but you make the "long hand" version look longer by adding a redundant if.. else. This would be a better comparison:

// Long-hand
const isVowel = (letter) => {
  return (
    letter === "a" ||
    letter === "e" ||
    letter === "i" ||
    letter === "o" ||
    letter === "u"
  );
};
Enter fullscreen mode Exit fullscreen mode

In point 4 I would recommend against nesting ternaries because you quickly get an unreadable mess of code, especially when the lines contain long strings which wrap in your editor.

Collapse
 
posandu profile image
Posandu

Nice post!

The 5th can be changed as follows

function f1() {
    // ...
}
function f2() {
    // ...
}

conditon ? f1() : f2();
Enter fullscreen mode Exit fullscreen mode

And the 6th can be improved by using Arrays

const dayNumber = new Date().getDay();

const days = [
    "Sunday",
    "Monday",
    "Tuesday",
    "Wednesday",
    "Thursday",
    "Friday",
    "Saturday",
];
// Or
const days = `Sunday,Monday,Tuesday,Wednesday,Thursday,Friday,Saturday`.split(
    ","
);

const day = days[dateNumber];
Enter fullscreen mode Exit fullscreen mode
Collapse
 
frankwisniewski profile image
Frank Wisniewski
    const weekday = new Intl.DateTimeFormat('de-DE',{weekday: 'long'}).format(new Date())
Enter fullscreen mode Exit fullscreen mode
Collapse
 
the_riz profile image
Rich Winter

Suggestion is a bit of a "premature optimization" - you just created a string " Sunday" instead of "Sunday"

With something like this, sometimes the longer way is just easier for the next guy to read. Especially when that next guy is you.

Collapse
 
ooling profile image
Sam oo LΓ­ng
(condition ? f1 : f2)();
Enter fullscreen mode Exit fullscreen mode

Is a new thing for me, but why'd you suggest

conditon ? f1() : f2();
Enter fullscreen mode Exit fullscreen mode

instead?

Collapse
 
posandu profile image
Posandu

If you need to add different arguments to each function call. You can't do it from the 1st method.

Thread Thread
 
ooling profile image
Sam oo LΓ­ng

ah so that's why..

Thread Thread
 
gorissomanuchi profile image
Gorisso-manuchi

hi my friend

Thread Thread
 
ooling profile image
Sam oo LΓ­ng

hello too

Collapse
 
spidermath profile image
Undefined Dev • Edited

Good job with the article, but I do have some things to say:
For #7, I'd rather go with the nullish coalescing operator(??) than ||...
And for #4, wouldn't it be a good idea to talk about why someone shouldn't use ternary operators too much as well, i.e., nested ternary operators can be a nightmare for readability, and recommending against it would be good for people who are learning about ternary operators.

Collapse
 
ignore_you profile image
Alex

Nested ternary would never pass my code review. IMO, one-liner is not an optimization if it affects readability.

Even though your #1 example is more general, this specific case can be shortened:

const isVowel = (letter) =>
  'aeiou'.indexOf(letter) > -1
Enter fullscreen mode Exit fullscreen mode
Collapse
 
nishithsavla profile image
Nishith Savla

I resist from using indexOf as you can instead use includes

'aeiou'.includes(letter)
Enter fullscreen mode Exit fullscreen mode
Collapse
 
rolandixor profile image
Roland Taylor

Some great tips here! Thanks for sharing!

Collapse
 
stefanthespider profile image
StefanTheSpider

I miss the unicorn πŸ₯²

Collapse
 
sharpweb profile image
WebSharp

thanks for sharing this stuff

Collapse
 
madza profile image
Madza

Some great tips right here, thanks πŸ‘πŸ’―

Collapse
 
timhuang profile image
Timothy Huang

Interesting and useful, thanks for sharing.

Some comments may only be visible to logged-in visitors. Sign in to view all comments.