JavaScript Finding if string in array can be found in an object

Question

I have an object that includes different roles and I have an array that includes specific colors.

What I want to do, is see if the roles.name includes any of the strings in the colors array. I've tried different approaches, such as:

var colors = ["blue", "yellow", "brown", "red", "green", "pink", "purple"];
var roles = [{"name": "asd"},
            {"name": "blue"},
            {"name": "yellow"},
            {"name": "brown"}, 
            {"name": "red"},
            {"name": "green"},
            {"name": "pink"},
            {"name": "purple"},
            {"name": "fgh"},
            {"name": "jkl"}];
for (var i = 0; i < roles.length; i++) {
    if (roles[i].name.indexOf(colors)) {
   console.log(roles[i].name);
  }
}

And

var colors = ["blue", "yellow", "brown", "red", "green", "pink", "purple"];
var roles = [{"name": "asd"},
            {"name": "blue"},
            {"name": "yellow"},
            {"name": "brown"}, 
            {"name": "red"},
            {"name": "green"},
            {"name": "pink"},
            {"name": "purple"},
            {"name": "fgh"},
            {"name": "jkl"}];
roles.forEach(role => {
    if (role.name.indexOf(colors)) {
    console.log(role.name);
  }
});

But with both of the codes, the result is the full list of roles.

Expected result is all colors logged to the console. What I get is all roles logged to the console.

In ES6 you can use Array#find and Array#findIndex, there is also Array#includes — Xotic750
– Xotic750, Commented Sep 23, 2016 at 23:54
Your object has all the keys with the same name, literally, they're all called name, so you overwrite the previous keys and values. — adeneo
– adeneo, Commented Sep 23, 2016 at 23:54
How are all the roles being logged when you're treating an object like an array? — Sterling Archer
– Sterling Archer, Commented Sep 23, 2016 at 23:55
The var roles is incorrect and is not in fact like that. I made a mistake in that part. They're all actually separate objects. I edited my question. — Wokki
– Wokki, Commented Sep 23, 2016 at 23:56

Barmar · Accepted Answer · 2016-09-23 23:58:37Z

3

You're using indexOf backwards. It should be array.indexOf(valueToSearchFor), but you have valueToSearchFor.indexOf(array). Also, indexOf returns the index, not a boolean; to test whether the element is found, you have to compare it to -1.

var colors = ["blue", "yellow", "brown", "red", "green", "pink", "purple"];
var roles = [{"name": "asd"},
        {"name": "blue"},
        {"name": "yellow"},
        {"name": "brown"}, 
        {"name": "red"},
        {"name": "green"},
        {"name": "pink"},
        {"name": "purple"},
        {"name": "fgh"},
        {"name": "jkl"}];
for (var i = 0; i < roles.length; i++) {
  if (colors.indexOf(roles[i].name) != -1) {
    console.log(roles[i].name);
  }
}

answered Sep 23, 2016 at 23:58

Barmar

789k57 gold badges554 silver badges669 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Wokki Over a year ago

Ah, I actually tried this approach but without the != -1. Didn't know it wouldn't return a boolean. Thank you.

Barmar Over a year ago

There's no excuse for that mistake. I'll bet every tutorial on using indexOf explains it.

BrTkCa · Accepted Answer · 2016-09-24 00:01:15Z

0

var colors = ["blue", "yellow", "brown", "red", "green", "pink", "purple"];
var roles = [{"name": "asd"}, {"name": "blue"}, {"name": "yellow"}, {"name": "brown"},{"name": "red"}, {"name": "green"}, {"name": "pink"}, {"name": "purple"}, {"name": "fgh"}, {"name": "jkl"}];
var discovered = [];
for (var i = 0; i < roles.length; i++) {
   for (var j=0 ; j < colors.length ; j++){
     if (roles[i].name == colors[j]) {
        discovered.push(roles[i]);
     }
   }
}

console.log(discovered);

answered Sep 24, 2016 at 0:01

BrTkCa

4,7894 gold badges28 silver badges46 bronze badges

Comments

JonDotsoy · Accepted Answer · 2016-09-24 00:01:32Z

0

Your roles is only an Object. Prefer this format.

    let colors = [
    {
        "name": "blue"
    },
    {
        "name": "yellow"
    },
    {
        "name": "brown"
    },
    {
        "name": "red"
    },
    {
        "name": "green"
    },
    {
        "name": "pink"
    },
    {
        "name": "purple"
    }
]

And It's each color with using .map()

colors.map(function (color) {
    console.log(color.name)
})

answered Sep 24, 2016 at 0:01

JonDotsoy

1142 silver badges4 bronze badges

Comments

Code Spirit · Accepted Answer · 2016-09-24 00:02:01Z

0

You switched out role and colors when calling indexOf. And ´indexOf´ doesnt return a ´boolean´ but an integer and if it returns 0 it would evaluate to ´false ´to which will cause wrong results.

roles.forEach(function (role) {
  if (colors.indexOf(role.name) >= 0) {
    console.log(role.name);
  }
});

answered Sep 24, 2016 at 0:02

Code Spirit

5,1776 gold badges30 silver badges50 bronze badges

Collectives™ on Stack Overflow

JavaScript Finding if string in array can be found in an object

4 Answers 4

2 Comments

Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

4 Answers 4

2 Comments

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related