javascript - 按值查找嵌套对象键

Question

I'm trying to find key of object which is containing my value.

There is my object:

var obj = {}

obj["post1"] = {
    "title":    "title1",
    "subtitle": "subtitle1"
}

obj["post2"] = {
    "title":    "title2",
    "subtitle": "subtitle2"
}

And now, I'm trying to get object key of value "title2"

function obk (obj, val) {
  const key = Object.keys(obj).find(key => obj[key] === val);
  return key
}

console.log(obk(obj, "title2"))

Output:

undefined

Desired output:

post2

Answer 1

You have to access the subkey of the object:

 function obk (obj, prop, val) {
   return Object.keys(obj).find(key => obj[key][prop] === val);
 }

 console.log(obk(obj, "title", "title2"));

Or you could search all values of the subobject:

 function obk (obj, val) {
   return Object.keys(obj).find(key => Object.values( obj[key] ).includes(val)); 
 }

 console.log(obk(obj, "title2"))

Answer 2

You can use array map:

 var obj = {} obj["post1"] = { "title": "title1", "subtitle": "subtitle1" } obj["post2"] = { "title": "title2", "subtitle": "subtitle2" } //console.log(obj); function obk (obj, val) { var result = ""; Object.keys(obj).map(key => { if(obj[key].title === val) result = key; }); return result; } console.log(obk(obj, "title2"));

Or use array find to optimize searching function:

 var obj = {} obj["post1"] = { "title": "title1", "subtitle": "subtitle1" } obj["post2"] = { "title": "title2", "subtitle": "subtitle2" } //console.log(obj); function obk (obj, val) { result = Object.keys(obj).find(key => { if(obj[key].title === val) return key; }); return result; } console.log(obk(obj, "title1"));

Answer 3

You pretty much have it, just add obj[key].title === val as mentioned by Chris G.

Here's an ES6 one liner that returns an array of all matches.

 var obj = {} obj["post1"] = { "title": "title1", "subtitle": "subtitle1" } obj["post2"] = { "title": "title2", "subtitle": "subtitle2" } const filterByTitle = (obj, title) => Object.values(obj).filter(o => o.title === title); console.log(filterByTitle(obj, 'title1'))