在javascript对象中查找元素的位置

Question

I have a javascript object. My console.log outputs this:

Object {1: "name", 2: "cost", 3: "country", 4: "date"}

How do I find the number that corresponds to "cost"? I'd like a function that outputs 2

Answer 1

Just iterate over the properties checking their respective values.

for (var property in object) {
  if (object[property] === 'cost') {
     /// congratulations, you've found it
  }
}

There are of course numerous fancy ways you can do this, eg Object.keys - but they are all fundamentally the same thing.

Answer 2

A non-loopy way of doing it would be:

 var yourObject = {1: "name", 2: "cost", 3: "country", 4: "date"}; var result = Object.keys(yourObject).find(key => yourObject[key] === 'cost'); console.log(result) // 2 

_{Assumes you can use ES6 (arrow functions, find )}

Answer 3

Figured I'd toss an answer in here since Object.Keys() isn't supported before IE9 from what I read.

$.each(yourObject, function(key,value){
    if(value === 'cost'){
        console.log(key) // key is 2
    }
});

Here's a JSFiddle .

Answer 4

Using loadash

_.invert(input).cost