@onesy/utils
Version:
86 lines (85 loc) • 3.33 kB
JavaScript
;
var __importDefault = (this && this.__importDefault) || function (mod) {
return (mod && mod.__esModule) ? mod : { "default": mod };
};
Object.defineProperty(exports, "__esModule", { value: true });
const is_1 = __importDefault(require("./is"));
const unique_1 = __importDefault(require("./unique"));
const optionsDefault = {
response: 'array',
};
// m - array
// m! / a! * b! * c! ...
function permutationWithRepetition(value_, options_ = {}) {
const options = Object.assign(Object.assign({}, optionsDefault), options_);
if ((0, is_1.default)('array', value_)) {
const value = (0, unique_1.default)(value_);
const length = value.length;
const items = (0, is_1.default)('number', options.items) ? options.items : length;
if (items < 1)
return [value];
if (items === 1)
return value.map(item_ => [item_]);
const item = new Array(items).fill(0);
let index = items - 2;
const response = [];
// Starts with all 0 indexes for all items
// it loops for the last position and makes each item for each index
// then, it moves to the left and increments the index by 1
// once item on left index increment moves over amount of items
// it resets to 0 index, and then it moves left and increments that item
// using same methodology, etc. until item at index 0 has index value === items.length
if (options.response === 'array') {
while (index >= 0) {
// Reset
index = items - 2;
for (let i = 0; i < length; i++) {
item[items - 1] = i;
response.push(item.map(index_ => value[index_]));
}
// Move to the left of the values
while (true) {
if (item[index] === length - 1) {
item[index] = 0;
index--;
if (index < 0)
break;
}
else {
item[index]++;
break;
}
}
}
return response;
}
if (options.response === 'yield')
return function* () {
while (index >= 0) {
// Reset
index = items - 2;
for (let i = 0; i < length; i++) {
item[items - 1] = i;
const item_ = item.map(index_ => value[index_]);
yield item_;
response.push(item_);
}
// Move to the left of the values
while (true) {
if (item[index] === length - 1) {
item[index] = 0;
index--;
if (index < 0)
break;
}
else {
item[index]++;
break;
}
}
}
return response;
};
}
}
exports.default = permutationWithRepetition;