nnnick/Chart.js

/**
 * @namespace Chart._adapters
 * @since 2.8.0
 * @private
 */

import type {AnyObject} from '../types/basic.js';
import type {ChartOptions} from '../types/index.js';

export type TimeUnit = 'millisecond' | 'second' | 'minute' | 'hour' | 'day' | 'week' | 'month' | 'quarter' | 'year';

export interface DateAdapter<T extends AnyObject = AnyObject> {
  readonly options: T;
  /**
   * Will called with chart options after adapter creation.
   */
  init(this: DateAdapter<T>, chartOptions: ChartOptions): void;
  /**
   * Returns a map of time formats for the supported formatting units defined
   * in Unit as well as 'datetime' representing a detailed date/time string.
   */
  formats(this: DateAdapter<T>): Record<string, string>;
  /**
   * Parses the given `value` and return the associated timestamp.
   * @param value - the value to parse (usually comes from the data)
   * @param [format] - the expected data format
   */
  parse(this: DateAdapter<T>, value: unknown, format?: TimeUnit): number | null;
  /**
   * Returns the formatted date in the specified `format` for a given `timestamp`.
   * @param timestamp - the timestamp to format
   * @param format - the date/time token
   */
  format(this: DateAdapter<T>, timestamp: number, format: TimeUnit): string;
  /**
   * Adds the specified `amount` of `unit` to the given `timestamp`.
   * @param timestamp - the input timestamp
   * @param amount - the amount to add
   * @param unit - the unit as string
   */
  add(this: DateAdapter<T>, timestamp: number, amount: number, unit: TimeUnit): number;
  /**
   * Returns the number of `unit` between the given timestamps.
   * @param a - the input timestamp (reference)
   * @param b - the timestamp to subtract
   * @param unit - the unit as string
   */
  diff(this: DateAdapter<T>, a: number, b: number, unit: TimeUnit): number;
  /**
   * Returns start of `unit` for the given `timestamp`.
   * @param timestamp - the input timestamp
   * @param unit - the unit as string
   * @param [weekday] - the ISO day of the week with 1 being Monday
   * and 7 being Sunday (only needed if param *unit* is `isoWeek`).
   */
  startOf(this: DateAdapter<T>, timestamp: number, unit: TimeUnit | 'isoWeek', weekday?: number): number;
  /**
   * Returns end of `unit` for the given `timestamp`.
   * @param timestamp - the input timestamp
   * @param unit - the unit as string
   */
  endOf(this: DateAdapter<T>, timestamp: number, unit: TimeUnit | 'isoWeek'): number;
}

function abstract<T = void>(): T {
  throw new Error('This method is not implemented: Check that a complete date adapter is provided.');
}

/**
 * Date adapter (current used by the time scale)
 * @namespace Chart._adapters._date
 * @memberof Chart._adapters
 * @private
 */
class DateAdapterBase implements DateAdapter {

  /**
   * Override default date adapter methods.
   * Accepts type parameter to define options type.
   * @example
   * Chart._adapters._date.override<{myAdapterOption: string}>({
   *   init() {
   *     console.log(this.options.myAdapterOption);
   *   }
   * })
   */
  static override<T extends AnyObject = AnyObject>(
    members: Partial<Omit<DateAdapter<T>, 'options'>>
  ) {
    Object.assign(DateAdapterBase.prototype, members);
  }

  readonly options: AnyObject;

  constructor(options: AnyObject) {
    this.options = options || {};
  }

  // eslint-disable-next-line @typescript-eslint/no-empty-function
  init() {}

  formats(): Record<string, string> {
    return abstract();
  }

  parse(): number | null {
    return abstract();
  }

  format(): string {
    return abstract();
  }

  add(): number {
    return abstract();
  }

  diff(): number {
    return abstract();
  }

  startOf(): number {
    return abstract();
  }

  endOf(): number {
    return abstract();
  }
}

export default {
  _date: DateAdapterBase
};