How do to a nested for loop in this example with javascript

Question

var data = [
    {
    "something": "something",
    "stages": [{
                "node": {"name": "test0"},
                "status": {"name": "test"},
                "time": {"name": "test"}
               },{
                "node": {"name": "test1"},
                "status": {"name": "test"},
                "time": {"name": "test"}
               }]
     }
];

nodeList = []

data.forEach(obj =>
  obj.stages.forEach(stage => if (nodeList.indexOf(stage.node.name) > -1) {
   nodeList.push({stage.node.name})
  );

I am trying to add the name to a list if that name does not already exist in the list. The above is not working.

The in operator gets you indexes. Use of operator of this.job[0].stage[i]. — m1k1o
– m1k1o, Commented Jun 3, 2019 at 23:09
for(... in ...) iterates through the keys in an object. In your example i is a string, not a stage. — JLRishe
– JLRishe, Commented Jun 3, 2019 at 23:09
Per JLRishe's comment, you possibly want for (node in this.job[0].stage[i]) { console.log(node.name) }. i is a property name, not a reference. You might also need function nodeName() { ... } . — RobG
– RobG, Commented Jun 3, 2019 at 23:24
this did not resolve the issue - I updated OP with a little more information — david
– david, Commented Jun 3, 2019 at 23:39
about a million syntax errors but that code you've updated in there is mostly right — WilliamNHarvey
– WilliamNHarvey, Commented Jun 4, 2019 at 17:24

WilliamNHarvey · Accepted Answer · 2019-06-04 17:24:59Z

2

For...in loops in javascript return strings, not objects. You can either continue treating it as a string, or parse it into an object to loop over.

Also totally confused about you redefining i, it's not going to work unless you make a different variable in your first loop

for (field in this.job[0].stages[i]) {
  console.log(field);
    for (node in this.job[0].stages[i][field]) {
      console.log(node);
      console.log(this.job[0].stages[i][field][node].name);
    }
}

EDIT:

here, from what you've put in the OP I've fixed your syntax errors

var data = [
  {
  "something": "something",
  "stages": [{
              "node": {"name": "test0"},
              "status": {"name": "test"},
              "time": {"name": "test"}
             },{
              "node": {"name": "test1"},
              "status": {"name": "test"},
              "time": {"name": "test"}
             }]
   }
];

nodeList = [];

data.forEach(obj =>
  obj.stages.forEach(stage => {
    if (nodeList.indexOf(stage.node.name) === -1) {
      return nodeList.push(stage.node.name)
    }
  })
);

edited Jun 4, 2019 at 17:24

answered Jun 3, 2019 at 23:49

WilliamNHarvey

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5 Comments

david Over a year ago

so this seems like the most elegant solution - I tried it and could not get it working. Then I realized the json example in OP was slightly out of order so I updated the json in the OP - hoping you can revise your answer to match this

WilliamNHarvey Over a year ago

what is i even? how does your line this.job[0].stages[i] work as you explained it did? i must be defined somewhere outside this function, right? If you don't want it then it would just be this answer without the [i] on lines 1, 3, and 5.

david Over a year ago

I added [i] because that was suggested in the answer below. No idea what i is or does. Hoping to find a solution

WilliamNHarvey Over a year ago

Ok well if it wasn't part of your original question then try this without the 3 i's on the lines i mentioned above. Your JSON in your question isn't real JSON in the first place (You're missing a closing bracket in each array value) so im just not really sure what you need here

david Over a year ago

I removed the i's and still does not work. I had a lot of sensitive data in the json so could not do a copy and paste - but tried again to update it in the OP more accurately

Indecisive · Accepted Answer · 2019-06-04 00:04:54Z

0

Why not try:

function nodeName () {
  if (this.job[ 0 ].stages[ 0 ]) {
    for (let i = 0; i < this.job[ 0 ].stages.length; i++) {
      let name = this.job[ 0 ].stages[ i ].node.name
      if (name)
        console.log(name) // "test"
    }
  }
}

answered Jun 4, 2019 at 0:04

Indecisive

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Comments

musicfuel · Accepted Answer · 2019-06-04 00:05:39Z

0

As the others were mentioning, the i is just a string in this case because it is the name of a key which is just a string. To get the value of i in your structure you need to fully reference the object using it again:

nodeName() {
  if (this.job[0].stages[0]) {
    for (i in this.job[0].stages[i]) {
      console.log(i);
      for (node in this.job[0].stages[i].node) {
        console.log(node.name)
      }
    }
  }
}

answered Jun 4, 2019 at 0:05

musicfuel

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Comments

RobG · Accepted Answer · 2019-06-04 06:00:19Z

Given the object literal you've added to the OP (and fixing the syntax errors), the data object is an array of objects which have a stages property.

stages is also an array of objects that have a node property, which is an object with a name property.

You shouldn't use for..in for arrays as the order is not guaranteed. Assuming that you need it to be, you should use forEach, which also makes the code much more concise:

var data = [
    {
    "something": "something",
    "stages": [{
                "node": {"name": "test0"},
                "status": {"name": "test"},
                "time": {"name": "test"}
               },{
                "node": {"name": "test1"},
                "status": {"name": "test"},
                "time": {"name": "test"}
               }]
     }
];

data.forEach(obj =>
  obj.stages.forEach(stage => console.log(stage.node.name))
);

with your answer, how would i add the names to a single list?
I was able to get mine working with your answer - right now I'm stuck though trying to replace console.log with adding node.name to a list (if it doesnt' already exist), I will probably make a new post for this question, but I updated the OP here anyway with the revised code

Jaya · Accepted Answer · 2019-06-04 06:37:50Z

Assuming you would like to print all the values for the name properties for each of the keys present, (ie) node, status and time, you could do the following,

var sampleJobs = [{
  "something": "something",
  "stages": [{
      "node": {
        "name": "node0-test"
      },
      "status": {
        "name": "status0-test"
      },
      "time": {
        "name": "time0-test"
      }
    },
    {
      "node": {
        "name": "node1-test"
      },
      "status": {
        "name": "status1-test"
      },
      "time": {
        "name": "time1-test"
      }
    }
  ]
}]

// outer for loop is for the array of the job object itself
for (i = 0; i < sampleJobs.length; i++) {
 
  // inner for loop is for the stages object within the outer job object
  for (j = 0; j < sampleJobs[i].stages.length; j++) {
    // this will print each object inside the stages array 
    // console.log(sampleJobs[i].stages[j]);

    // now am making an assumption that you want to print the value for "name" property foreach of the keys, here is how you do it
    // this will print the name value for all the keys present in the object
    
  Object.keys(sampleJobs[i].stages[j]).forEach(e => {
       console.log(sampleJobs[i].stages[j][e]["name"])
    })
 
  }

}

Note: Feel free to comment or uncomment the console statements which i have placed here as they are all for undertanding purpose only.

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