In ECMAScript 6 you can use computed values for object keys: var CONSTANT_A = 0, CONSTANT_B = 1 var state_machine = { [CONSTANT_A]: function () { return ‘a’ }, [CONSTANT_B]: function () { return ‘b’ } }; console.log(state_machine) This does not work in Internet Explorer 11 nor in Safari browsers: https://kangax.github.io/compat-table/es6/#test-object_literal_extensions_computed_properties
Try this: function isEmpty(map) { for(var key in map) { if (map.hasOwnProperty(key)) { return false; } } return true; } Your solution works, too, but only if there is no library extending the Object prototype. It may or may not be good enough.
Everything in JavaScript is an object. In the case of an Array, the length property returns the size of the internal storage area for indexed items of the array. Some of the confusion may come into play in that the [] operator works for both numeric and string arguments. For an array, if you use … Read more
Unlike PHP which conflates arrays and hashes, in Ruby (and practically every other language) they’re a separate thing. http://ruby-doc.org/core/classes/Hash.html In your case it’d be: a = {‘Peter’ => 32, ‘Quagmire’ => ‘asdas’} There are several freely available introductory books on ruby and online simulators etc. http://www.ruby-doc.org/
The terminology in js can be confusing at first, so lets straighten that out first. Yes, pretty much everything in js is an object. However, there are differences in the data types. An array can be used like as associative array, but its different than an object literal. var x = []; //array var y … Read more