I've been trying to solve this challenge (found at jschallenger.com):
This is my solution so far (Which I was sure would work):
function insertEveryThree(a, b) {
let arr = a.split('')
for (let i = arr.length - 3; i > 0; i -= 3) {
arr.splice(i, 0, b)
}
return arr.join('')
}
console.log(insertEveryThree('actionable', '-')) // a-cti-ona-ble
console.log(insertEveryThree('1234567', '.')) // 1.234.567
console.log(insertEveryThree('abcde', '$')) // ab$cde
console.log(insertEveryThree('zxyzxyzxyzxyzxyz', 'w')) // zwxyzwxyzwxyzwxyzwxyzWhere am I failing at?
You could replace the string with a regular expression.
function insertEveryThree(a, b) {
return a.replace(/(?=(...)+$)/g, b);
}
console.log(insertEveryThree('actionable', '-')) // a-cti-ona-ble
console.log(insertEveryThree('1234567', '.')) // 1.234.567
console.log(insertEveryThree('abcde', '$')) // ab$cde
console.log(insertEveryThree('zxyzxyzxyzxyzxyz', 'w')) // zwxyzwxyzwxyzwxyzwxyzYou need to push into a new array, splicing mutates the array and causes problems with indexes:
function insertEveryThree(str, character, index = 3) {
const strArr = str.split("");
const newArr = [];
for (const i = 0; i < str.length; i++) {
newArr.push(strArr[i]);
if ((i + 1) % index === 0 && i !== 0 && i + 1 < str.length) {
newArr.push(character);
}
}
return newArr.join("");
}
console.log(insertEveryThree("actionable", "-")); // act-ion-abl-e
console.log(insertEveryThree("1234567", ".")); // 123.456.7
console.log(insertEveryThree("abcde", "$")); // abc$de
console.log(insertEveryThree("zxyzxyzxyzxyzxyz", "w")); // zxywzxywzxywzxywzxywz