Get value by key from array javascript -


i'm experiencing issue getting value javascript array.

var color = new array(); (var = 0; < datafeatures.length - 1; i++) {     color[datafeatures[i].properties.userid] = datafeatures[i].properties.linecolor; }  snapshot.foreach(function (childsnapshot) {      var colour = childsnapshot.wp_user;      console.log(color[colour]);      console.log(json.stringify(color));      console.log(color);      console.log(colour); }

console.log result:

color[colour]: undefined

json.stringify(color): []

color: 

[]  26: "#9d36ee"  45: "#b1c743"  56: "#f9c53c"  61: "#d770ce"  63: "#267fa1"  64: "#85002f"  68: "#78eca8"  92: "#a4a2e7" length: 93 __proto__: array(0)

colour: 61

expected output color[colour]: "#d770ce"

real output color[colour]: undefined.

color has in it, colour number (key), seems impossible value color..

you might want try changing line

var color = new array();

to 

var color = {};

what may looking not array but, term in javascript, object.

edit

after looking @ source , doing debugging, problem seems asynchronous executions. you're color variable being populated @ later time, explains why json.stringify produces empty object when printing console.log maintains reference variable.

you'll want ensure color variable populated first.

some steps on how debugged this, (using chrome):

  • open chrome dev tools (ctrl+shift+i)
  • go console
  • click on line number prints undefined
  • you should sent sources tab you'll see source code
  • here add breakpoint clicking on line number (407, in case)
  • refresh while on dev tools window, (ctrl+r)
  • the javascript execution should stop @ debugger
  • in state mouse on variables on source codes see values @ point in time
  • you'll find color indeed empty object
  • so trace how color being populated
  • find nested under code d3.json(
  • that's when know got asynchronous problem

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