array not iterating through each element

Question

Below is the response from the backend :

results = [{
    "name": "FantasticBeasts",
    "count": 546809,
  },

  {
    "name": "SSIPOS",
    "count": 16257,
  },

  {
    "name": "xyz",
    "count": 16257,
  }
]

for (var i = 0; i <= results.length; i++) {
  console.log('result ==>', results[i]);
}

My end goal is to fetch the name from every element of the array. But before that, I need to iterate over the array elements. But I am unable to iterate through the array elements.

result ==> undefined

Condition should be i < results.length; as index starts from 0 — Satpal
– Satpal, Commented Jan 18, 2019 at 8:26
The error is like @Satpal says: You might do this error again in the future, but someday the syntax of iterating over an array is that common to your mind that it is ideomatic and you will do it automatically in the correct way — yunzen
– yunzen, Commented Jan 18, 2019 at 8:35

Alexandre Elshobokshy · Accepted Answer · 2019-01-18 08:28:17Z

4

It should be i < results.length because with a <= you're comparing an additional non existing value.

results = [{
    "name": "FantasticBeasts",
    "count": 546809,
  },

  {
    "name": "SSIPOS",
    "count": 16257,
  },

  {
    "name": "xyz",
    "count": 16257,
  }
]

for (var i = 0; i < results.length; i++) {
  console.log('result ==>', results[i]);
}

answered Jan 18, 2019 at 8:28

Alexandre Elshobokshy

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3 Comments

Aditya Over a year ago

the output is displaying with every character in the result for example: result ==> { result ==> " result ==> n .....

Adrian Pop Over a year ago

@Aditya and what output do you actually expect? This is how the console prints the results.

jburtondev Over a year ago

@Aditya this answer solves the problem (I have also upvoted it), but using a forEach is more advisable as discussed in my answer.

Umair Mohammad · Accepted Answer · 2019-01-18 10:19:46Z

4

In javascript arrays are 0 indexed so, there are 0 to length-1 indexes. So we need to run loop accordingly from 0 to < length or <= length-1

results = [{
    "name": "FantasticBeasts",
    "count": 546809,
  },

  {
    "name": "SSIPOS",
    "count": 16257,
  },

  {
    "name": "xyz",
    "count": 16257,
  }
]

for (var i = 0; i < results.length; i++) {
  console.log("Name:", results[i].name, "Count:", results[i].count);
}

results.forEach(function(result) {
  console.log("Name:", result.name, "Count:", result.count);
});

forEach is bit more cleaner way to achieve the same result.

Reference : https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/forEach

edited Jan 18, 2019 at 10:19

answered Jan 18, 2019 at 8:31

Umair Mohammad

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Comments

veben · Accepted Answer · 2019-01-18 08:29:29Z

2

You iterate from 0 to array.length-1. So you have to replace:

i <= results.length;

by:

i < results.length;

answered Jan 18, 2019 at 8:29

veben

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Comments

jburtondev · Accepted Answer · 2019-01-18 08:31:41Z

1

Using a forEach is more efficient in this case, as it's more testable and gives you more control without having to manually access the index.

results.forEach(r => console.log(`result ==> ${r.name}`));

answered Jan 18, 2019 at 8:31

jburtondev

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Comments

Alberto · Accepted Answer · 2019-01-18 09:11:35Z

0

You can also have a look at .forEach and then passing by reference the function (no parameters).

results.forEach(console.log);

This will console log each Result.

answered Jan 18, 2019 at 9:11

Alberto

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