getEveryNthWithCondition.js
994 Bytes
"use strict";
Object.defineProperty(exports, "__esModule", {
value: true
});
exports.getEveryNthWithCondition = getEveryNthWithCondition;
/**
* Given an array and a number N, return a new array which contains every nTh
* element of the input array. For n below 1, an empty array is returned.
* If isValid is provided, all candidates must suffice the condition, else undefined is returned.
* @param {T[]} array An input array.
* @param {integer} n A number
* @param {Function} isValid A function to evaluate a candidate form the array
* @returns {T[]} The result array of the same type as the input array.
*/
function getEveryNthWithCondition(array, n, isValid) {
if (n < 1) {
return [];
}
if (n === 1 && isValid === undefined) {
return array;
}
var result = [];
for (var i = 0; i < array.length; i += n) {
if (isValid === undefined || isValid(array[i]) === true) {
result.push(array[i]);
} else {
return undefined;
}
}
return result;
}