function to return key of object if given value

Question

If given an object such as:

  taste =
    0: "Hate"
    1: "Really Dislike"
    2: "Dislike"
    3: ""
    4: "Like"
    5: "Really Like"
    6: "Love"

I am looking of a function that will return the key if given the value. I tried the following

  Object::getKeyByVal = (value) ->
    for prop of this
      return prop  if this[prop] is value  if @hasOwnProperty(prop)

Using this, alert time.getKeyByVal("< 1.5 hours") will acutally return 8, but it gives an error that kills the rest of the script;

Uncaught TypeError: Object function (value) {
      var prop;
      for (prop in this) {
        if (this.hasOwnProperty(prop) ? this[prop] === value : void 0) {
          return prop;
        }
      }
    } has no method 'exec'

Is there a better way of getting the key of a given value?

mpm · Accepted Answer · 2013-02-11 04:54:12Z

1

try this :

getKeyFromValue = (obj,value)->
  for own k,v of obj
    if v==value
      return k

o =
  a:1
  b:2
  c:3
  d:4

console.log(getKeyFromValue(o,3)) # should output c

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answered Feb 11, 2013 at 4:54

mpm

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