5 ms·

> (Caveat: Iteration over collections is not yet specified) Is this a joke? Is not iterating over dictionaries and arrays javascript's most glaring weakness?

• stevejohnson 15y ago
  My guess would be bikeshedding.
• JoshTriplett 15y ago
  Remember that the spec won't come out for a while, after a pile of additional development. Also remember that we have to live with it for a long time, so taking the time to get it right seems preferable.
• tikhonj 15y ago
  There is a foreach that works: .forEach(). And when you're not just iterating over an array but transforming it, you have map(), reduce() and filter().
  • herge 15y ago
    Is it really too much to ask to have some syntactic sugar. Is for i,v in blah , where i is an index of an array, or a key (not a property!) of a dictionary really too much to ask in 2012? No wonder people are using coffeescript.
    • jashkenas 15y ago
      CoffeeScript's got you covered. Here's forEach ... for item, index in list ... here's the same over an object ... for key, value of object ... here's the map() ... mapped = for item in list ... here's the filter() ... filtered = for item in list when item.isActive ... and so on.
      • herge 15y ago
        Exactly. The number one thing javascript should take from coffeescript is the iteration syntax.
    • cmf028 15y ago
      ecmascript 6 will also introduce for of loops which is said to fix for in. checkout wiki.ecmascript.org for all the ecmascript 6/harmony niceness
• samth 15y ago
  A different way to put it is: "the best way to iterate over collections is still being discussed, because we want to get it right". Also, for `Map`, how do you think `foreach` should work? Should the function be called with (a) the key, (b) the value, (c) an array with both the key and the value, (d) the key and the value as separate arguments? Similarly, in the statement: for(let x of some_map) { ... } should `x` range over the keys, values, or key-value pairs of the map?