1 var toPrimitive = require('../internals/to-primitive');
2 var isSymbol = require('../internals/is-symbol');
4 // `ToPropertyKey` abstract operation
5 // https://tc39.es/ecma262/#sec-topropertykey
6 module.exports = function (argument) {
7 var key = toPrimitive(argument, 'string');
8 return isSymbol(key) ? key : key + '';