/**
*
* @param {String} start The first letter
* @param {String} end The last letter
* @param {Number} step The step between letter
* @returns {Array} Return a new array of charCode between start and end
*/
function codeRange(start, end, step = 1) {
return new Array(Math.ceil((end.charCodeAt(0) - start.charCodeAt(0)) / step))
.fill(start.charCodeAt(0))
.map((x, i) => i * step + start.charCodeAt(0));
}
/**
* A specialized version of `_.map` for arrays without support for callback
* shorthands and `this` binding.
*
* @private
* @param {Array} array The array to iterate over.
* @param {Function} iteratee The function invoked per iteration.
* @returns {Array} Returns the new mapped array.
*/
function arrayMap(array, iteratee) {
var index = -1,
length = array.length,
result = Array(length);
while (++index < length) {
result[index] = iteratee(array[index], index, array);
}
return result;
}
const codes = codeRange("A", "H", 2);
// find the iteratee code to map string from charCode
const Letters = arrayMap(codes, --?--);
console.table(Letters);
┌─────────┬────────┐
│ (index) │ Values │
├─────────┼────────┤
│ 0 │ 'A' │
│ 1 │ 'C' │
│ 2 │ 'E' │
│ 3 │ 'G' │
└─────────┴────────┘
