javascript JSON access

Question

I have a JSON object that goes somewhat like this:

var waitingGames = {
 arithemetic:[
 {
 games:[]
 },
 {
 games:[]
 },
 {
 games:[]
 }
 ]

and so on for synonyms, antonyms and translation. My problem is that I can't seem to access the games array by using this:

var gametype = url_parts.query.type;
var gamesize = url_parts.query.size;
if(games.waitingGames.gametype[gamesize].games.length == 0)

I get that gametype is undefined, even though I already tried printing the variable and it has the right value (arithemetic in the above example). Any ideas how to fix this?

• nbrooks: possible duplicate of Using variable keys to access values in JavaScript objects
• nbrooks: If your key name is stored in a variable, you have to reference it using the bracket notation object[variableName]. It makes sense that dot-notation wouldn't work since object.variableName implies that there is a property of the object named variableName, when it should be keyName, which is just stored in the variable.
• Monokilho: Don't know if this is relative, but I'm getting this JSON object by using require: var games = require('./gameJSONobj')

Answer 1

Please try

if(games.waitingGames.arithemetic[gamesize].games.length == 0)

• Monokilho: that would kinda ruin the point because im trying to pass to the function where it should be getting then games information from. Either way, like that I also get the cannot read property of 'arithemetic' of undefined".
• nbrooks: @user3152485 waitingGames is a variable name, not an object property, so you can't reference it by saying games.waitingGames -- that's why it's undefined.
• Monokilho: That might be it.. any suggestion to go around it? because games has 3 variables inside it all too big to keep the main file clean.
• Durgaprasad Budhwani: Can you paste your complete json object so that we can help you in better way ??

Answer 2

Use:

games.waitingGames[gametype][gamesize].games.length

Here you are using gametype as a variable like you meant to.

See this proof-of-concept JSFiddle demo.

• Monokilho: like that i get a "unexpected token [" error,also tried without the dot and i get " cannot read property of 'arithemetic' of undefined =/
• Robin: Sorry, typo on the ., edited. Shouldn't gametype be equal to "arithmetic"?
• Robin: Also, where are you defining games? Does it work if you just write: games[gametype][gamesize].games.length
• Monokilho: Yes, games is defined although from an explanation from above it might it it since i have var games = require(./gameJSONobj); and being waitingGames a variable inside that file, it won't work with the dot reference

Answer 3

You can access the value from inner games object using this expresson console.log(waitingGames.arithemetic[0].games);

Use a for loop to loop through arithemetic array.

for(var i =0, j = waitingGames.arithemetic.length; i<j; i++){
 if(waitingGames.arithemetic.games.length == 0){
 }
}

Answer 4

Fixed, had to use the brackets to change use the variable content to reach where i wanted inside the JSON object, thanks all