What is the syntax for implementing a nested for loop in JavaScript within this particular scenario?

Question

What is the syntax for implementing a nested for loop in JavaScript within this particular scenario?

var entries = [
    {
    "item": "something",
    "steps": [{
                "node": {"name": "test0"},
                "status": {"name": "test"},
                "time": {"name": "test"}
               },{
                "node": {"name": "test1"},
                "status": {"name": "test"},
                "time": {"name": "test"}
               }]
     }
];

customList = []

entries.forEach(data => {
    data.steps.forEach(step => {
        if (customList.indexOf(step.node.name) === -1) {
            customList.push(step.node.name)
        }
    });
});

I am attempting to append the name to a list only if it is not already present in the list. However, the code provided above seems to be malfunctioning.

javascript vue.js

Answer 1

Answer №1

When working with for...in loops in JavaScript, it's important to remember that they return strings, not objects. You have the option to treat the result as a string or parse it into an object before looping over it.

I noticed that you were redefining i, which would cause issues unless you create a different variable for your initial 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:

Based on the information provided in the OP, I've corrected the syntax errors in your code snippet.

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)
    }
  })
);

Answer 2

When working with for...in loops in JavaScript, it's important to remember that they return strings, not objects. You have the option to treat the result as a string or parse it into an object before looping over it.

I noticed that you were redefining i, which would cause issues unless you create a different variable for your initial 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:

Based on the information provided in the OP, I've corrected the syntax errors in your code snippet.

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)
    }
  })
);

Answer 3

Answer №2

Consider this:

function getNodeNames () {
  if (this.task[0].steps[0]) {
    for (let j = 0; j < this.task[0].steps.length; j++) {
      let nodeName = this.task[0].steps[j].node.name;
      if (nodeName) {
        console.log(nodeName); // "test"
      }
    }
  }
}

Answer 4

Consider this:

function getNodeNames () {
  if (this.task[0].steps[0]) {
    for (let j = 0; j < this.task[0].steps.length; j++) {
      let nodeName = this.task[0].steps[j].node.name;
      if (nodeName) {
        console.log(nodeName); // "test"
      }
    }
  }
}

Answer 5

Answer №3

Like previously mentioned by others, the i is being used as a string here because it represents the name of a key in this scenario. To retrieve the value of i within your structure, you must reference the object using it once more:

getNodeName() {
  if (this.job[0].stages[0]) {
    for (index in this.job[0].stages[index]) {
      console.log(index);
      for (nodeIndex in this.job[0].stages[index].node) {
        console.log(node.name)
      }
    }
  }
}

Answer 6

Like previously mentioned by others, the i is being used as a string here because it represents the name of a key in this scenario. To retrieve the value of i within your structure, you must reference the object using it once more:

getNodeName() {
  if (this.job[0].stages[0]) {
    for (index in this.job[0].stages[index]) {
      console.log(index);
      for (nodeIndex in this.job[0].stages[index].node) {
        console.log(node.name)
      }
    }
  }
}

Answer 7

Answer №4

After adding the object literal to the original post and correcting any syntax errors, it appears that the data object is an array of objects containing a property named stages.

Within each object in the stages array, there is another array of objects with a property called node, which in turn contains a property named name.

It's recommended not to use for..in loops for arrays due to unpredictable order. Instead, you can utilize forEach to achieve the desired results while keeping the code 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))
);

Answer 8

After adding the object literal to the original post and correcting any syntax errors, it appears that the data object is an array of objects containing a property named stages.

Within each object in the stages array, there is another array of objects with a property called node, which in turn contains a property named name.

It's recommended not to use for..in loops for arrays due to unpredictable order. Instead, you can utilize forEach to achieve the desired results while keeping the code 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))
);

Answer 9

Answer №5

If you wish to display all the values of the name properties associated with each key such as node, status, and time, here's how you can achieve it:

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"
      }
    }
  ]
}]

// The outer for loop iterates over the array containing job objects
for (i = 0; i < sampleJobs.length; i++) {
 
  // The inner for loop goes through the stages object within each 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]);

    // Assuming you want to display the value of the "name" property for each key, here is how to do it
    // This code snippet prints the name value for all 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 included for understanding purposes.

Answer 10

If you wish to display all the values of the name properties associated with each key such as node, status, and time, here's how you can achieve it:

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"
      }
    }
  ]
}]

// The outer for loop iterates over the array containing job objects
for (i = 0; i < sampleJobs.length; i++) {
 
  // The inner for loop goes through the stages object within each 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]);

    // Assuming you want to display the value of the "name" property for each key, here is how to do it
    // This code snippet prints the name value for all 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 included for understanding purposes.

What is the syntax for implementing a nested for loop in JavaScript within this particular scenario?

Answer №1

Answer №2

Answer №3

Answer №4

Answer №5

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