@nullvoxpopuli/ember-composable-helpers/src/utils/as-array.ts

Composable helpers for Ember

import EmberArray, { isArray } from '@ember/array';
import EmberObject, { get } from '@ember/object';

import type ArrayProxy from '@ember/array/proxy';

function isIterable(value: unknown) {
  return Symbol.iterator in Object(value);
}

// from https://github.com/flexyford/ember-power-select/blob/78a5430c1ac89daf315d0801fd5201e444e82434/addon/components/power-select.ts
function isArrayable<T>(thing: unknown): thing is EmberArray<T> {
  return typeof (thing as EmberArray<T>).toArray === 'function';
}

function isPromiseLike<T>(thing: unknown) {
  return typeof (thing as Promise<T>).then === 'function';
}

function isPromiseProxyLike<T>(thing: unknown): thing is ArrayProxy<T> {
  return (
    isPromiseLike(thing as Promise<T>) &&
    Object.hasOwnProperty.call(thing, 'content')
  );
}

function toExtendable<T>(array: T[]) {
  if (!Object.isExtensible(array)) {
    return Array.from(array);
  } else {
    return array;
  }
}

export default function asArray<T>(maybeArray: T[]): T[] {
  return toExtendable(_asArray(maybeArray));
}

function _asArray<T>(maybeArray: unknown): T[] {
  if (typeof maybeArray === 'number') {
    throw new Error(
      'Numbers not supported as arrays [ember-composable-helpers]',
    );
  }
  if (typeof maybeArray === 'string') {
    return maybeArray.split('') as T[];
  }
  // for perf-reasons falling back to e-array, instead of using it first
  if (Array.isArray(maybeArray)) {
    return maybeArray;
  } else if (isArray(maybeArray)) {
    return maybeArray as T[];
  } else if (typeof maybeArray === 'object' && maybeArray === null) {
    return [];
  } else if (typeof maybeArray === 'undefined') {
    return [];
  } else if (maybeArray instanceof Set) {
    return Array.from(maybeArray.values());
  } else if (maybeArray instanceof Map) {
    return Array.from(maybeArray.values());
  } else if (maybeArray instanceof WeakMap) {
    throw new Error(
      'WeakMaps is not supported as arrays [ember-composable-helpers]',
    );
  } else if (maybeArray instanceof WeakSet) {
    throw new Error(
      'WeakSets is not supported as arrays [ember-composable-helpers]',
    );
  }
  if (typeof maybeArray === 'object') {
    if (isPromiseProxyLike(maybeArray)) {
      // eslint-disable-next-line ember/no-get -- TODO: Revisit this
      const content = get(maybeArray, 'content');
      if (typeof content !== 'object' || content === null) {
        throw new Error(
          'Unknown content type in array-like object [ember-composable-helpers]',
        );
      }
      if (isArrayable(content)) {
        return (content as EmberArray<T>).toArray();
      } else {
        return _asArray(content);
      }
    }
    if (isPromiseLike(maybeArray)) {
      throw new Error(
        'Promise-like objects is not supported as arrays [ember-composable-helpers]',
      );
    }
    if (isArrayable(maybeArray)) {
      return (maybeArray as EmberArray<T>).toArray();
    }
    if (maybeArray instanceof EmberObject) {
      throw new Error(
        'EmberObjects is not supported as arrays [ember-composable-helpers]',
      );
    }
    return Array.from(Object.values(maybeArray));
  }
  if (!maybeArray) {
    return [];
  }
  if (!isIterable(maybeArray)) {
    throw new Error(
      'Argument, passed as array is not iterable [ember-composable-helpers]',
    );
  }
  return maybeArray as T[];
}