7 Shorthand Optimization Tricks every JavaScript Developer Should Know 😎
Tapajyoti Bose
Posted on October 30, 2022
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:
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);
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) {
// ...
}
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];
// ...
}
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;
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";
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)();
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];
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";
That's all folks! 🎉
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Posted on October 30, 2022
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