如何访问对象的Javascript 2D数组？

Question

I have a global array that I declare as

var fileMappings = [];

I do some work, and add a row to the array like so:

fileMappings.push({ buttonNumber: number, audioFile: file });

if I do a JSON.stringify(fileMappings) I get this:

[{“buttonNumber”:”btn11”,”audioFile”:{0A0990BC-8AC8-4C1C-B089-D7F0B30DF858}},
{“buttonNumber”:”btn12”,”audioFile”:{2FCC34A6-BD1A-4798-BB28-131F3B546BB6}},
{“buttonNumber”:”btn13”,”audioFile”:{53A206EC-7477-4E65-98CC-7154B347E331}}]

How can I access the GUID for "btn11", etc?

Answer 1

Since Javascript arrays don't have support for keys, I would suggest that you use an object. Otherwise, you have to iterate through the entire array every time to look for the desired key.

var fileMappings = {};

And instead of push() , define a new property :

fileMappings[number] = { buttonNumber: number, audioFile: file };

This way, you can access your object with fileMappings['btn11']

Answer 2

You can iterate over the array's members to find the button, then return its GUID:

function findGUID(arr, buttonNumber) {
  for (var i=0, iLen=arr.length; i<iLen; i++) [
    if (arr[i].buttonNumber == buttonNumber) {
      return arr[i].audioFile;
    }
  }
  // return undefined - buttonNumber not found
}

Or if you want to use ES5 features:

function getGUID(arr, buttonNumber) {
  var guid;
  arr.some(function(obj) {
             return obj.buttonNumber == buttonNumber && (guid = obj.audioFile);
           });
  return guid;
}

but I think the first is simpler and easier to maintain.