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:

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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