Return row from object array

Question

I have an object array that contains states. It has three fields (id, name, abbr)

To simplify things, I'll use three states:

states: any = [{
      "stateId": 3,
      "stateName": "Arizona",
      "stateAbbreviation": "AZ"
    },
    {
      "stateId": 4,
      "stateName": "Arkansas",
      "stateAbbreviation": "AR"
    },
    {
      "stateId": 5,
      "stateName": "California",
      "stateAbbreviation": "CA"
    }]

I have a provider where I want to return an object if it matches the stateId I pass it.

So in my provider I have the following funciton:

  getState(stateId){
    this.states.forEach(function(element) {
      if(element.stateId == stateId){
        return element;
      }  
    });
  }

In my home controller I simply call it like this:

console.log('State is: ', this.states.getState(50));

But I'm getting the error: undefined.

What am I doing wrong?

Sachila Ranawaka · Accepted Answer · 2018-06-26 06:13:50Z

1

Need to return the result of. So add a return statement. Also use the fitler operator instead forEach

getState(stateId){
    return this.states.filter(function(element) {
      if(element.stateId == stateId){
        return element;
      }  
    });
  }

Demo

edited Jun 26, 2018 at 6:13

answered Jun 26, 2018 at 6:08

Sachila Ranawaka

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1 Comment

cnak2 Over a year ago

Hi Sachila, that didn't work. I still get undefined.

ssougnez · Accepted Answer · 2018-06-26 06:11:25Z

0

Alternatively, you could use the filter function:

getState(stateId){
  return this.states.filter(function(element) {
    return element.stateId == stateId);
  });
}

Note the first return statement used to return the result of the filter function.

answered Jun 26, 2018 at 6:11

ssougnez

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Comments

Dinh Duong · Accepted Answer · 2018-06-26 06:14:56Z

0

Your problem because forEach not return everything.

In typescript you can try this one.

getState(stateId) {
    return this.states.find(x => x.stateId == stateId);
}

answered Jun 26, 2018 at 6:14

Dinh Duong

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Comments

Vikas · Accepted Answer · 2018-06-26 06:35:55Z

0

From Docs
forEach() executes the callback function once for each array element; unlike map() or reduce() it always returns the value undefined and is not chainable

You need filter() method
Modified Code

 getState(stateId){


      return this.states.filter(element=> {
          if(element.stateId == stateId){
            return element;
          }  
        });
      }

Live Demo;

Or you could use find() method

getState(stateId){
    return this.states.find(element=> {
      if(element.stateId == stateId){
        return element;
      }  
    });

Live Demo

filter() runs till the end of the array, and invokes its callback on every item; in contrast to find() which stops after having found one.

edited Jun 26, 2018 at 6:35

answered Jun 26, 2018 at 6:28

Vikas

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