deepDiffer() — react Function Reference

Source Code

packages/react-native-renderer/src/__mocks__/react-native/Libraries/ReactPrivate/deepDiffer.js lines 16–70

function deepDiffer(
  one: any,
  two: any,
  maxDepthOrOptions: Options | number = -1,
  maybeOptions?: Options,
): boolean {
  const options =
    typeof maxDepthOrOptions === 'number' ? maybeOptions : maxDepthOrOptions;
  const maxDepth =
    typeof maxDepthOrOptions === 'number' ? maxDepthOrOptions : -1;
  if (maxDepth === 0) {
    return true;
  }
  if (one === two) {
    // Short circuit on identical object references instead of traversing them.
    return false;
  }
  if (typeof one === 'function' && typeof two === 'function') {
    // We consider all functions equal unless explicitly configured otherwise
    let unsafelyIgnoreFunctions =
      options == null ? null : options.unsafelyIgnoreFunctions;
    if (unsafelyIgnoreFunctions == null) {
      unsafelyIgnoreFunctions = true;
    }
    return !unsafelyIgnoreFunctions;
  }
  if (typeof one !== 'object' || one === null) {
    // Primitives can be directly compared
    return one !== two;
  }
  if (typeof two !== 'object' || two === null) {
    // We know they are different because the previous case would have triggered
    // otherwise.
    return true;
  }
  if (one.constructor !== two.constructor) {
    return true;
  }
  if (Array.isArray(one)) {
    // We know two is also an array because the constructors are equal
    const len = one.length;
    if (two.length !== len) {
      return true;
    }
    for (let ii = 0; ii < len; ii++) {
      if (deepDiffer(one[ii], two[ii], maxDepth - 1, options)) {
        return true;
      }
    }
  } else {
    for (const key in one) {
      if (deepDiffer(one[key], two[key], maxDepth - 1, options)) {
        return true;
      }
    }