Adding JSON data to Ionic 2

Question

Adding JSON data to Ionic 2

I've been utilizing Ionic 2 Storage to store form data persistently. The method I use for saving the data is as follows:

this.storage.set(key, JSON.stringify(formData));

When it comes to retrieving and updating the stored data, here's what I do:

this.getReport(key).then((report) => {
  var objReport = JSON.parse(report);
  objReport.push(data); //this is where the issue arises
  this.storage.set(pk, JSON.stringify(objReport));
});

The getReport function looks like this:

getReport(key) {
  return this.storage.get(key);
}

Although I'm aware that .push is meant for arrays and not objects, constantly converting between them isn't ideal due to the size of the objects I'm working with.

So my question is: What would be the most efficient approach to retrieve JSON from storage and append to it? It seems illogical to me that .parse returns an object when objects lack a push method similar to arrays.

Here's the error I'm encountering:

Runtime Error Uncaught (in promise): TypeError: Cannot read property 'push' of undefined TypeError: Cannot read property 'push' of undefined

javascript json ionic2

Answer 1

Answer №1

When this error occurs, it indicates that there are currently no records associated with that key. To address this issue, you will need to perform a check similar to the following:

this.fetchData(key).then((data) => {
  var newData = [];//initialize an empty Array
  if(data){ //if there is data available for the specified key
     newData = JSON.parse(data); //parse the data and assign it to newData
  }
  newData.push(info); //This step will be executed whether or not there was existing data
  this.saveData(pk, JSON.stringify(newData));
});

Answer 2

When this error occurs, it indicates that there are currently no records associated with that key. To address this issue, you will need to perform a check similar to the following:

this.fetchData(key).then((data) => {
  var newData = [];//initialize an empty Array
  if(data){ //if there is data available for the specified key
     newData = JSON.parse(data); //parse the data and assign it to newData
  }
  newData.push(info); //This step will be executed whether or not there was existing data
  this.saveData(pk, JSON.stringify(newData));
});

Adding JSON data to Ionic 2

Answer №1

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