export function deepEqual()

in packages/charts/src/utils/fast_deep_equal.ts [37:94]

• 41 lines of code
• 37 McCabe index (conditional complexity)

export function deepEqual(a: any, b: any, partial = false): boolean {
  if (a === b) return true;

  if (a && b && typeof a === 'object' && typeof b === 'object') {
    if (a.constructor !== b.constructor) return false;

    let length: number;
    let i: any;

    if (Array.isArray(a)) {
      length = a.length;
      if (length !== b.length) return false;
      for (i = length; i-- !== 0; ) if (!deepEqual(a[i], b[i])) return false;
      return true;
    }
    if (a instanceof Map && b instanceof Map) {
      if (a.size !== b.size) return false;
      // @ts-ignore - 3rd party code
      for (i of a.entries()) if (!b.has(i[0])) return false;
      // @ts-ignore - 3rd party code
      for (i of a.entries()) if (!deepEqual(i[1], b.get(i[0]))) return false;
      return true;
    }

    if (a instanceof Set && b instanceof Set) {
      if (a.size !== b.size) return false;
      // @ts-ignore - 3rd party code
      for (i of a.entries()) if (!b.has(i[0])) return false;
      return true;
    }

    if (a.constructor === RegExp) return a.source === b.source && a.flags === b.flags;
    if (a.valueOf !== Object.prototype.valueOf) return a.valueOf() === b.valueOf();
    if (a.toString !== Object.prototype.toString) return a.toString() === b.toString();

    const keys = Object.keys(a);
    length = keys.length;
    if (length !== Object.keys(b).length && !partial) return false;

    for (i = length; i-- !== 0; ) if (!Object.prototype.hasOwnProperty.call(b, keys[i] ?? '')) return false;

    for (i = length; i-- !== 0; ) {
      const key = keys[i];
      if (!key || (key === '_owner' && a.$$typeof)) {
        // React-specific: avoid traversing React elements' _owner.
        //  _owner contains circular references
        // and is not needed when comparing the actual elements (and not their owners)
        continue;
      }
      if (!deepEqual(a[key], b[key])) return false;
    }

    return true;
  }

  // true if both NaN, false otherwise
  return a !== a && b !== b;
}