Javascript populate array with IF statement

Question

Is there a way to populate an array with if condition inside?

example

cars = [
  {id:1,color:'red'},
  {id:2,color:'blue'},
  {id:3,color:'blue'}
]

I need to create a new array that will get the value of ID and a new field which is type.

if color = red, type = 1, else type = 0.

I tried this one but it will not work for javascript.

var newArray = [
   for(var car in cars){
       newId: car.id,
       if(car.color == 'red'){
          type: '1',
       else
          type: '0'
   }
]

the return value should be

newArray = [
       {newId:1,type:'1'},
       {newId:2,type:'0'},
       {newId:3,type:'0'}
]

Help please

wrong object you have specified : cars =[ [id:1,color:red], [id:2,color:blue], [id:3,color:blue] ]; — binariedMe
– binariedMe, Commented Jun 22, 2017 at 4:08
Your array / object syntax is incorrect. Each car entry should probably look like {id:1,color:'red'} — Phil
– Phil, Commented Jun 22, 2017 at 4:12
Should the new object type property be the number 1 or 0, or the string "1" or "0"? Your question shows it both ways. "dont mind the syntax this is just a representation" - Why would you not use standard JS object literal syntax as shown in all of the answers? — nnnnnn
– nnnnnn, Commented Jun 22, 2017 at 4:13
I fixed the syntax to use object literals where appropriate. I hope that's ok — Phil
– Phil, Commented Jun 22, 2017 at 4:19

Phil · Accepted Answer · 2017-06-23 03:39:22Z

4

You can easily map your original array to a new one

const cars = [{"id":1,"color":"red"},{"id":2,"color":"blue"},{"id":3,"color":"blue"}]

const newArray = cars.map(car => ({
  newId: car.id,
  type: car.color === 'red' ? '1' : '0'
}))

console.info(newArray)

If you need to support IE, this will work in v9+

var newArray = cars.map(function(car) {
  return {
    newId: car.id,
    type: car.color === 'red' ? '1' : '0'
  }
})

Versions of IE prior to 9 do not support Array.prototype.map. See this pollyfill if you need to support those.

edited Jun 23, 2017 at 3:39

answered Jun 22, 2017 at 4:10

Phil

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7 Comments

Rey Norbert Besmonte Over a year ago

Cool! this one is the best answer and working for me. I will follow this. Thank you so much.

Rey Norbert Besmonte Over a year ago

hi phil, will be possible if you can write the if statement as string? As i need to apply this to a string problem. I just used a representation of a small sample to show my problem

Phil Over a year ago

@ReyNorbertBesmonte do you mean that the "1" and "0" values should be strings? If so, you were asked to clarify that here

Rey Norbert Besmonte Over a year ago

yup.. lets make it if red = "this is red", else "this is not red"

Rey Norbert Besmonte Over a year ago

I got it working thank you so much... It seems it has a compatibility issue on IE. It said it has syntax error. I need to find a solution for this one. Working Fine in Edge, Firefox, and Chrome.

|

GullDe · Accepted Answer · 2017-06-22 04:10:38Z

1

I believe this is what you are looking for:

var newArray = [];
for(var car in cars) {
    var obj = {newId: car.id};
    if(car.color === 'red') {
        obj['type'] = '1';
    } else {
        obj['type'] = '0';
    }
    newArray.push(obj);
}

answered Jun 22, 2017 at 4:10

GullDe

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Comments

binariedMe · Accepted Answer · 2017-06-22 04:32:13Z

1

Given array is wrong, If your array looks like this :

cars =[
  {id:1,color:"red"},
  {id:2,color:"blue"},
  {id:3,color:"blue"}
];

then you should do this :

var newArray = cars.map((car) => { let type; if(car.color === "blue") type = 1; else type = 0; return { id: car.id, color: car.color, type }})

edited Jun 22, 2017 at 4:32

answered Jun 22, 2017 at 4:10

binariedMe

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1 Comment

Phil Over a year ago

This modifies the original values. Doesn't look like OP wants to do that

Sholeman · Accepted Answer · 2017-06-22 04:18:40Z

0

That's what the Array Map function is for, You can create from another array.

However, your array is wrong and it has been corrected in the code below:

cars =[
    {id:1,color:'red'},
    {id:2,color:'blue'},
    {id:3,color:'blue'}
]
newCarArray=cars.map(function(car){
    if(car.color =='red'){
         return {newId:car.id, type:1}
    }
     return {newId:car.id, type:0}
})
console.log (newCarArray)

answered Jun 22, 2017 at 4:18

Sholeman

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Comments

YCotov · Accepted Answer · 2017-06-22 04:19:10Z

0

Try this instead your code:

     var newArray = [];
      for(var car in cars){
         if(car.color == 'red'){
             newArray.push({newId: car.id,type: '1'});
           } else {
              newArray.push({newId: car.id,type: '0'});
           }
       }

edited Jun 22, 2017 at 4:19

answered Jun 22, 2017 at 4:13

YCotov

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1 Comment

YCotov Over a year ago

sorry, 2nd should be type = 0

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