Cannot get properties of javascript object

Question

I have a for loop that adds properties to the data object

words is an array of strings

for (let i = 0; i < words.length; i++) {
  let word = words[i];
  data[word] = i;
}

After that, my objext looks like this:

data = {"the": 0, "of": 1, "and": 2, "to": 3, "a": 4, …};

I have tried

data['the'];

but it returns undefined

How do I retrieve the value of the property?

Here is my full code

let vocab = {};

$.ajax({
  url: "10000words.txt",
  success: function(data) {
    data = data.split(/\n/).slice(0, 10000);
    for (let i = 0; i < data.length; i++) {
      let word = data[i];
      vocab[word] = i;
    }
    console.log(vocab['test']);
  }
});

When I type vocab into the console, it prints out vocab but when I try vocab['the'] it returns undefined

data['the'] works fine. You're doing something else wrong. Please provide an stackoverflow.com/help/mcve — SLaks
– SLaks, Commented Jul 19, 2018 at 23:33
@bena The question was whether you’re trying to access vocab outside the success callback, not whether you’ve declared it outside. Your issue is impossible to reproduce, if you didn’t actually access vocab outside of success. That’s why I think the most likely issue is this: Why is my variable unaltered after I modify it inside of a function? - Asynchronous code reference — Sebastian Simon
– Sebastian Simon, Commented Jul 19, 2018 at 23:45
@bena Actually… try console.log([...Object.keys(vocab).find((word) => /t[^a-z]*h[^a-z]*e/.test(word))]); and see whether it matches ["t", "h", "e"]. There may be invisible characters within your words, thus vocab.the won’t work. — Sebastian Simon
– Sebastian Simon, Commented Jul 20, 2018 at 0:17

Roman Mahotskyi · Accepted Answer · 2018-07-19 23:33:19Z

1

Here is an example of how to get a value by the object key.

const words = ['Hello', 'world'];
const data = {};

for(let i = 0; i < words.length; i++) {
  const word = words[i];
  data[word] = i;
}

const index = data['Hello'];

document.write(index);

answered Jul 19, 2018 at 23:33

Roman Mahotskyi

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