polygerrit-ui/app/utils/common-util.ts

/**
 * @license
 * Copyright (C) 2020 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/**
 * @fileoverview Functions in this file contains some widely used
 * code patterns. If you noticed a repeated code and none of the existing util
 * files are appropriate for it - you can wrap the code in a function and put it
 * here. If you notice that several functions can be group together - create
 * a separate util file for them.
 */

/**
 * Wrapper for the Object.prototype.hasOwnProperty method
 */
// eslint-disable-next-line @typescript-eslint/no-explicit-any
export function hasOwnProperty(obj: any, prop: PropertyKey) {
  // Typescript rules don't allow to use obj.hasOwnProperty directly
  return Object.prototype.hasOwnProperty.call(obj, prop);
}

// TODO(TS): move to common types once we have type utils
//  Required for constructor signature.
// eslint-disable-next-line @typescript-eslint/no-explicit-any
export type Constructor<T> = new (...args: any[]) => T;

/**
 * Use the function for compile-time checking that all possible input
 * values are processed
 */
export function assertNever(obj: never, msg: string): never {
  console.error(msg, obj);
  throw new Error(msg);
}

/**
 * Throws an error with the provided error message if the condition is false.
 */
export function check(
  condition: boolean,
  errorMessage: string
): asserts condition {
  if (!condition) throw new Error(errorMessage);
}

/**
 * Throws an error if the property is not defined.
 */
export function checkProperty(
  condition: boolean,
  propertyName: string
): asserts condition {
  check(condition, `missing required property '${propertyName}'`);
}

/**
 * Throws an error if the property is not defined.
 */
export function checkRequiredProperty<T>(
  property: T,
  propertyName: string
): asserts property is NonNullable<T> {
  if (property === undefined || property === null) {
    throw new Error(`Required property '${propertyName}' not set.`);
  }
}

/**
 * Throws an error if the property is not defined.
 */
export function assertIsDefined<T>(
  val: T,
  variableName = 'variable'
): asserts val is NonNullable<T> {
  if (val === undefined || val === null) {
    throw new Error(`${variableName} is not defined`);
  }
}

export function queryAll<E extends Element = Element>(
  el: Element,
  selector: string
): NodeListOf<E> {
  if (!el) throw new Error('element not defined');
  const root = el.shadowRoot ?? el;
  return root.querySelectorAll<E>(selector);
}

export function query<E extends Element = Element>(
  el: Element | null | undefined,
  selector: string
): E | undefined {
  if (!el) return undefined;
  if (el.shadowRoot) {
    const r = el.shadowRoot.querySelector<E>(selector);
    if (r) return r;
  }
  return el.querySelector<E>(selector) ?? undefined;
}

export function queryAndAssert<E extends Element = Element>(
  el: Element | null | undefined,
  selector: string
): E {
  const found = query<E>(el, selector);
  if (!found) throw new Error(`selector '${selector}' did not match anything'`);
  return found;
}

/**
 * Returns true, if both sets contain the same members.
 */
export function areSetsEqual<T>(a: Set<T>, b: Set<T>): boolean {
  if (a.size !== b.size) {
    return false;
  }
  return containsAll(a, b);
}

/**
 * Returns true, if 'set' contains 'subset'.
 */
export function containsAll<T>(set: Set<T>, subSet: Set<T>): boolean {
  for (const value of subSet) {
    if (!set.has(value)) {
      return false;
    }
  }
  return true;
}

/**
 * Add value, if the set does not contain it. Otherwise remove it.
 */
export function toggleSetMembership<T>(set: Set<T>, value: T): void {
  if (set.has(value)) {
    set.delete(value);
  } else {
    set.add(value);
  }
}

export function unique<T>(item: T, index: number, array: T[]) {
  return array.indexOf(item) === index;
}