iter-tools-es/impls/$deep-equal/deep-equal.js

The iterable toolbox

const {
  isIterable,
  isWrappable
} = require('../../internal/iterable.js');

const {
  __map
} = require('../$map/map.js');

const {
  __every
} = require('../$every/every.js');

const {
  __zipAll
} = require('../$zip-all/zip-all.js');

const {
  __sliceFromStart
} = require('../$slice/slice.js');

const none = Symbol('none');
const zipAllConfig = {
  filler: none
};

const empty = function* () {};

const iterableOrEmpty = value => value == null ? empty() : value;

function _deepEqual(values, same, isIterable, depth = 0) {
  if (__every(values, value => typeof value !== 'string' && isIterable(value))) {
    for (const stepValues of __zipAll(__map(values, iterableOrEmpty), zipAllConfig)) {
      if (!_deepEqual(stepValues, same, isIterable, depth + 1)) return false;
    }
  } else {
    const firstValue = values[0];

    for (const value of __sliceFromStart(values, 1)) {
      if (!same(value, firstValue, depth)) return false;
    }
  }

  return true;
}

exports._deepEqual = _deepEqual;

function __deepEqual(values, same = Object.is, coerceNil = true) {
  return values.length <= 1 ? true : _deepEqual(values, same, coerceNil ? isWrappable : isIterable);
}

exports.__deepEqual = __deepEqual;

function deepEqual(...values) {
  return __deepEqual(values);
}

exports.deepEqual = deepEqual;