GetMethod.js

'use strict';

var GetIntrinsic = require('../GetIntrinsic');

var $TypeError = GetIntrinsic('%TypeError%');

var GetV = require('./GetV');
var IsCallable = require('./IsCallable');
var IsPropertyKey = require('./IsPropertyKey');

/**
 * 7.3.9 - https://ecma-international.org/ecma-262/6.0/#sec-getmethod
 * 1. Assert: IsPropertyKey(P) is true.
 * 2. Let func be GetV(O, P).
 * 3. ReturnIfAbrupt(func).
 * 4. If func is either undefined or null, return undefined.
 * 5. If IsCallable(func) is false, throw a TypeError exception.
 * 6. Return func.
 */

module.exports = function GetMethod(O, P) {
	// 7.3.9.1
	if (!IsPropertyKey(P)) {
		throw new $TypeError('Assertion failed: IsPropertyKey(P) is not true');
	}

	// 7.3.9.2
	var func = GetV(O, P);

	// 7.3.9.4
	if (func == null) {
		return void 0;
	}

	// 7.3.9.5
	if (!IsCallable(func)) {
		throw new $TypeError(P + 'is not a function');
	}

	// 7.3.9.6
	return func;
};