flat-iter

Deeply Iterate over Arrays. Like calling array.flat()[Symbol.iterator](), but without the memory cost.

what's wrong with flat()?

There's nothing "wrong" with flat for most cases, but if you have a really large array of numbers, running flat() will create a new array potentially greatly increasing your memory consumption and crashing your application.

what's the solution?

Create an iterator that iterates over a nested array's values one by one without creating a new array.

install

npm install flat-iter

usage

import flatIter from "flat-iter";

const data = [
  [123, 342, 452, 533, ...],
  [1263, 432, 234, 542, ...]
];

const iterator = flatIter(data, depth);

case study: calculating statistics

The calc-stats library calculates statistics of an iterable of numbers. It works on flat arrays or any iterable that returns numbers. It expects each call of next to return a number, not an array of numbers (like a row). By using flatIter we can calculate statistics for a table of numbers (2-D arrays).

// calculate statistics for 2-D Data
import calcStats from "calc-stats";

// new memory-safe way
const stats = calcStats(flatIter(data));

// old way, risking memory blowing up
const stats = calcStats(data.flat());