invoke.js

import applyStr from './apply-str';

/**
  Checks to see if the `methodName` exists on the `obj`.

  ```javascript
  let foo = { bar: function() { return 'bar'; }, baz: null };

  Ember.canInvoke(foo, 'bar'); // true
  Ember.canInvoke(foo, 'baz'); // false
  Ember.canInvoke(foo, 'bat'); // false
  ```

  @method canInvoke
  @for Ember
  @param {Object} obj The object to check for the method
  @param {String} methodName The method name to check for
  @return {Boolean}
  @private
*/
export function canInvoke(obj, methodName) {
  return obj !== null && obj !== undefined && typeof obj[methodName] === 'function';
}

/**
  Checks to see if the `methodName` exists on the `obj`,
  and if it does, invokes it with the arguments passed.

  ```javascript
  let d = new Date('03/15/2013');

  Ember.tryInvoke(d, 'getTime');              // 1363320000000
  Ember.tryInvoke(d, 'setFullYear', [2014]);  // 1394856000000
  Ember.tryInvoke(d, 'noSuchMethod', [2014]); // undefined
  ```

  @method tryInvoke
  @for Ember
  @param {Object} obj The object to check for the method
  @param {String} methodName The method name to check for
  @param {Array} [args] The arguments to pass to the method
  @return {*} the return value of the invoked method or undefined if it cannot be invoked
  @public
*/
export function tryInvoke(obj, methodName, args) {
  if (canInvoke(obj, methodName)) {
    return applyStr(obj, methodName, args);
  }
}