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src/traits/Injectable.js

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 * BSD 3-Clause License
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 * Copyright (c) 2018, MapCreator
 * All rights reserved.
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 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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import ResourceBase from '../resources/base/ResourceBase';
import { hasTrait, isParentOf } from '../utils/reflection';
import Trait from './Trait';

/**
 * Adds the possibility to inject proxies/methods
 *
 * @mixin
 */
export default class Injectable extends Trait {
  /**
   * Inject proxies and methods during the constructor
   */
  initializer () {
    const injectable = this.constructor._injectable || {};

    for (const name of Object.keys(injectable)) {
      const { value, isProxy } = injectable[name];

      if (isProxy) {
        this.injectProxy(name, value);
      } else {
        this.inject(name, value);
      }
    }
  }

  /**
   * Inject a proxy property into future instances
   *
   * @param {string|object} name - Name of the property
   * @param {function?} value - Either a resource or a function that returns a proxy
   *
   * @example
   *
   * Maps4News.injectProxy({Domain});
   *
   * // After creating new api instance
   *
   * api.domains // returns proxy
   */
  static injectProxy (name, value) {
    if (value) {
      if (typeof this._injectable === 'undefined') {
        this._injectable = {};
      }

      this._injectable[name] = { value, isProxy: true };
    } else {
      // Handle vue-style injections `.inject({ Foo, Bar, Baz })`
      for (const key of Object.keys(name)) {
        this.inject(key, name[key]);
      }
    }
  }

  /**
   * Inject a property into future instances
   *
   * @param {string|object} name - Name of the property
   * @param {function?} value - Any function that does not return a proxy
   *
   */
  static inject (name, value) {
    if (value) {
      if (typeof this._injectable === 'undefined') {
        this._injectable = {};
      }

      this._injectable[name] = { value, isProxy: false };
    } else {
      // Handle vue-style injections `.inject({ Foo, Bar, Baz })`
      for (const key of Object.keys(name)) {
        this.inject(key, name[key]);
      }
    }
  }

  /**
   * Prevent a property from being injected
   * @param {string} name - Name of the property
   */
  static uninject (name) {
    if (typeof this._injectable !== 'undefined') {
      delete this._injectable[name];
    }
  }

  /**
   * Inject a proxy
   * @param {string} name - Name of the property
   * @param {function?} value - Either a resource or a function that returns a proxy
   */
  injectProxy (name, value) {
    if (!value) {
      // Handle vue-style injections `.inject({ Foo, Bar, Baz })`
      for (const key of Object.keys(name)) {
        this.injectProxy(key, name[key]);
      }
    } else if (isParentOf(ResourceBase, value)) {
      this._injectProxy(name, value);
    } else {
      this._inject(name, value);
    }
  }

  /**
   * Inject a property into the instance
   *
   * @param {string|object} name - Name of the property
   * @param {function?} value - Any function that does not return a proxy
   *
   */
  inject (name, value) {
    this._inject(name, value, false);
  }

  /**
   * Revert a proxy injection in instance, won't delete non-injected properties
   *
   * @param {string} name - property name
   * @throws Error when the property was not injected
   */
  uninject (name) {
    const descriptor = Object.getOwnPropertyDescriptor(this, name);
    const value = descriptor.value || descriptor.get || {};

    if (!value.injected) {
      throw new Error(`Property "${name}" was not injected, can't un-inject`);
    }

    if (value.original) {
      Object.defineProperty(this, name, value.original);
    } else {
      Object.defineProperty(this, name, {
        // eslint-disable-next-line no-undefined
        value: undefined,
        enumerable: false,
        writable: true,
      });
    }
  }

  _injectProxy (name, value) {
    if (name === value.name) {
      name = `${name.replace(/^\w/, c => c.toLowerCase())}s`;
    }

    const OwnableResource = require('./OwnableResource').default;

    if (hasTrait(value, OwnableResource)) {
      const OwnedResourceProxy = require('../proxy/OwnedResourceProxy').default;

      this._inject(name, function () {
        return new OwnedResourceProxy(this.api, this, value);
      });
    } else if (isParentOf(ResourceBase, value) && this._proxyResourceList) {
      // returns a SimpleResourceProxy
      this._inject(name, function () {
        return this._proxyResourceList(value);
      });
    } else {
      const ResourceProxy = require('../proxy/ResourceProxy').default;

      this._inject(name, function () {
        return new ResourceProxy(this, value);
      });
    }
  }

  _inject (name, value, getter = true) {
    const func = (...args) => value.apply(this, args);
    const original = Object.getOwnPropertyDescriptor(this, name);

    func.injected = true;

    // Store the original property descriptor if available
    if (original) {
      func.original = original;
    }

    Object.defineProperty(this, name, {
      enumerable: false,
      configurable: true,

      [getter ? 'get' : 'value']: func,
    });
  }
}