In this article I will share with you some really handy JavaScript tips.
Let’s get started!
1. Run the event listener only once.
If you want to add an event listener but have it run only once, you can use the once option:
element.addEventListener('click', () => console.log('I run only once'), {
once: true
}); 2. console.log variable wrapping
You can wrap your console.log() arguments with curly brackets to see their names. It’s a shorthand for logging objects:
3. Remove duplicate elements from an array:
const numbers = [2, 3, 4, 4, 2];
console.log([...new Set(numbers)]); // [2, 3, 4]4. Remove all falsy values from an array:
const myArray = [1, undefined, NaN, 2, null, '@denicmarko', true, 3, false];
console.log(myArray.filter(Boolean)); // [1, 2, "@denicmarko", true, 3] 5. Short-circuit conditionals
If you have to execute a function only if the condition is true, you can use short-circuit.
//If you have to execute a function only if the condition is true:
if (condition) {
doSomething();
}
// You can use short-circuit:
condition && doSomething(); 6. DRY
Don’t repeat yourself.
const myTech = 'JavaScript';
const techs = ['HTML', 'CSS', 'JavaScript'];
// Instead of:
if (myTech === 'HTML' || myTech === 'CSS' || myTech === 'JavaScript') {
// do something
}
// You can:
if (techs.includes(myTech)) {
// do something
} 7. Get the min/max value from an array
You can use Math.min() or Math.max() combined with the spread operator to find the minimum or maximum value in an array.
const numbers = [6, 8, 1, 3, 9];
console.log(Math.max(...numbers)); // 9
console.log(Math.min(...numbers)); // 1 8. Sum an array
You can use the reduce method to calculate the sum of all elements in an array:
const myArray = [10, 20, 30, 40];
const reducer = (total, currentValue) => total + currentValue;
console.log(myArray.reduce(reducer)); // 100 9. Copy to clipboard
You can use the Clipboard API to create the “Copy-to-clipboard” functionality, but note that it only works in secure contexts (HTTPS):
function copyToClipboard(text) {
return navigator.clipboard.writeText(text)
.then(() => {
console.log('Text copied to clipboard!');
})
.catch(err => {
console.error('Failed to copy text: ', err);
});
}Which JavaScript tip is your favorite? Let me know!