@onesy/utils
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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 equalDeep_1 = __importDefault(require("./equalDeep"));
const optionsDefault = {
response: 'array',
};
// m - array
// m!
function permutation(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 = length;
if (items < 1)
return [value];
if (items === 1)
return value.map(item_ => [item_]);
if (items === 2)
return [value, [value[1], value[0]]];
// And other use case, we have less items than the amount of values
// [0, 1, 2, 3, 4], or whatever
const allIndexes = [...Array(length).keys()];
let item = [...Array(items).keys()];
let index = items - 3;
let updated = false;
const response = [];
if (options.response === 'array') {
while (index >= 0) {
if (updated) {
index = items - 3;
updated = false;
}
// Add item to response
response.push(item.slice().map(index_ => value[index_]));
// Swap last two and add item to response
[item[length - 2], item[length - 1]] = [item[length - 1], item[length - 2]];
response.push(item.slice().map(index_ => value[index_]));
if (item[0] === length - 1 && item[1] === length - 2 && (0, equalDeep_1.default)(item, value.slice().reverse()))
break;
// Move to the left of the values
while (true) {
const firstPart = item.slice(0, index + 1);
const indexNew = allIndexes.filter(index_ => index_ > item[index] && firstPart.indexOf(index_) === -1)[0];
if (!indexNew) {
index--;
if (index < 0)
break;
updated = true;
}
else {
// Increment the index
// Make rest of the items unique based on the left over indexes from allIndexes
item[index] = indexNew;
// Make rest of item values unique based on all the left values
const part = item.slice(0, index + 1);
item = [...part, ...allIndexes.filter(i_ => part.indexOf(i_) === -1).slice(0, items - part.length)];
break;
}
}
}
return response;
}
if (options.response === 'yield')
return function* () {
while (index >= 0) {
if (updated) {
index = items - 3;
updated = false;
}
// Add item to response
let item_ = item.slice().map(index_ => value[index_]);
yield item_;
response.push(item_);
// Swap last two and add item to response
[item[length - 2], item[length - 1]] = [item[length - 1], item[length - 2]];
item_ = item.slice().map(index_ => value[index_]);
yield item_;
response.push(item_);
if (item[0] === length - 1 && item[1] === length - 2 && (0, equalDeep_1.default)(item, value.slice().reverse()))
break;
// Move to the left of the values
while (true) {
const firstPart = item.slice(0, index + 1);
const indexNew = allIndexes.filter(index_ => index_ > item[index] && firstPart.indexOf(index_) === -1)[0];
if (!indexNew) {
index--;
if (index < 0)
break;
updated = true;
}
else {
// Increment the index
// Make rest of the items unique based on the left over indexes from allIndexes
item[index] = indexNew;
// Make rest of item values unique based on all the left values
const part = item.slice(0, index + 1);
item = [...part, ...allIndexes.filter(i_ => part.indexOf(i_) === -1).slice(0, items - part.length)];
break;
}
}
}
return response;
};
}
}
exports.default = permutation;