iter-tools-es/impls/$flat/flat.js

The iterable toolbox

const {
  iterableCurry,
  isLoopable
} = require('../../internal/iterable.js');

const {
  validateArgs
} = require('./internal/validate-args.js');

const defaultShouldFlat = value => typeof value !== 'string' && isLoopable(value);

function* flatInternal(shouldFlat, depth, currentDepth, source) {
  for (const value of source) {
    if (currentDepth < depth && shouldFlat(value)) {
      yield* flatInternal(shouldFlat, depth, currentDepth + 1, value);
    } else {
      yield value;
    }
  }
}

function __flat(source, depth = 1, shouldFlat = defaultShouldFlat) {
  return flatInternal(shouldFlat, depth, 0, source);
}

exports.__flat = __flat;
const flat = /*#__PURE__*/iterableCurry(__flat, {
  minArgs: 0,
  maxArgs: 2,
  validateArgs
});
exports.flat = flat;