We all know that JavaScript is great but sometimes we face some difficulties that we have to find solutions for.
In this article, I will share with you some tricks that you may need someday.
Convert all array elements to string
In this example, we are using the built-in javascript method .map() to loop around the elements and convert them to strings.
function allToString(array) {
return array.map(elm => {
return Array.isArray(elm) ? allToString(elm) : elm.toString()
})
}
allToString([1, 2, 3, [4]])
// 👉 [ '1', '2', '3', [ '4' ] ]
Create a range of numbers
The range() function returns a sequence of numbers, starting from a specified number, and stops at a specified number.
function range(from, to) {
return Array((to - from) + 1).fill(0).map(() => from++)
}
range(1, 10)
// 👇
// [
// 1, 2, 3, 4, 5,
// 6, 7, 8, 9, 10
// ]
Check if a property exists in the object
var obj = {
a: 1,
b: 2,
c: 3
}
var aExists = !!obj['a'] // true
var rExists = !!obj['r'] // false
var uExists = !!obj['u'] // false
Remove a property from an object
We use the keyword delete that deletes both the value of the property and the property itself.
var obj = {
name: 'John',
age: 23,
country: 'UK'
}
// Usage
delete obj.country;
// 👇
// {
// name: 'John',
// age: 23
// }
Replace empty strings in object with null values
In this trick, we loop around the keys of our object and replace it with a null if it's an empty string.
var obj = {
a: '💎',
b: '✨',
c: '',
d: '🔮'
}
function replaceEmpty(object) {
if (!object || typeof object !== "object") return;
let newValues = Object.values(object).map(v => v.trim() ? v : null);
let objectKeys = Object.keys(object);
for (let i = 0; i < objectKeys.length; i++) {
object[objectKeys[i]] = newValues[i]
}
return object
}
// Usage
replaceEmpty(obj)
// 👇
// {
// a: '💎',
// b: '✨',
// c: null,
// d: '🔮'
// }
Return the longest string from an array of strings
Sorting the array using the built-in method .sort() made it easy. I sorted the array descending according to the length of the strings, then I return the first element of the array.
var arr = ['Hashnode', 'is', 'cool']
function findLongest(array) {
return arr.sort((a, b) => b.length - a.length)[0]
}
// Usage
findLongest(arr)
// 👉 "Hashnode"
Check if all array elements are equal
The method .every() checks every element of the array, and tells us if they are all equal to the first one.
var arr1 = [true, true, true]
var arr2 = [false, true, true]
var arr3 = [1, 2, 3]
var check = (array) => new Set(array).size <= 1
// Usage
check(arr1) // true
check(arr2) // false
check(arr3) // false
Reverse a string
To implement this trick, follow these steps:
- Split the string into an array of letters using
.split("")
["H", "a", "s", "h", "n", "o", "d", "e"]
- Reverse the array using
.reverse()
["e", "d", "o", "n", "h", "s", "a", "H"]
- And now, turn the letters into a string again using
.join("")
"edonhsaH"
const reverse = (string) => string.split("").reverse().join("")
// Usage
reverse("Hello, World!") // !dlroW ,olleH
reverse("Hashnode") // edonhsaH
reverse("ABC") // CBA
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