iteragain
Version:
Javascript Iterable/Iterator/Generator-function utilities.
43 lines • 1.5 kB
JavaScript
"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.ProductIterator = void 0;
const toArray_1 = require("../toArray");
/** Returns the cartesian product of the input `iterators`. */
class ProductIterator {
constructor(iterators, repeat) {
this.done = false;
this.pools = [];
this.i = 0;
const iterated = iterators.map(toArray_1.default);
for (let i = 0; i < repeat; i++)
this.pools.push(...iterated);
this.indices = new Array(this.pools.length).fill(0);
}
[Symbol.iterator]() {
return this;
}
next() {
if (this.done)
return { done: true, value: undefined };
const value = this.indices.map((v, i) => this.pools[i][v]);
for (this.i = 0; this.i < this.indices.length; this.i++) {
if (this.indices[this.pools.length - this.i - 1] < this.pools[this.pools.length - this.i - 1].length - 1) {
this.indices[this.pools.length - this.i - 1]++;
break;
}
}
if (this.i === this.indices.length) {
this.done = true;
return { done: false, value };
}
this.i--;
while (this.i >= 0) {
this.indices[this.pools.length - this.i - 1] = 0;
this.i--;
}
return { done: false, value };
}
}
exports.ProductIterator = ProductIterator;
exports.default = ProductIterator;
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