ObservableArray: add a new column

ObservableArray: add a new column

Posted by: lucas.gagneten on 29 April 2019, 4:38 pm EST

• 

  lucas.gagneten

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  Posted 29 April 2019, 4:38 pm EST

  Hello,
  
  I have an ```
  
  ObservableArray

  [
  
  0: {time: 16:22:30 , y0: 74.60}
  
  1: {time: 16:23:42, y0: 74.89}
  
  2: {time: 16:24:54 , y0: 75.52}
  
  3: {time: 16:26:06, y0: 75.46}
  
  …]

  
  I need to add a new column, like this:
  

  [
  
  0: {y1: 55.71}
  
  1: {y1: 55.45}
  
  2: {y1: 54.28}
  
  3: {y1: 54.15}
  
  …]

  
  So, the result should be:
  

  [
  
  0: {time: 16:22:30 , y0: 74.60 , y1: 55.71}
  
  1: {time: 16:23:42, y0: 74.89 , y1: 55.45}
  
  2: {time: 16:24:54 , y0: 75.52 , y1: 54.28}
  
  3: {time: 16:26:06, y0: 75.46, y1: 54.15}
  
  …]

  
  How can I add the column "y1" to the array?
  Thanks

• 

  bernardo-castilho

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  Posted 29 April 2019, 9:23 pm EST

  Hello!

  The ObservableArray really is a JavaScript array, so you can add properties to the objects in the ObservableArray as you would with a regular array. For example:

  arr.forEach((item, index) => {
    item.y1 = index * 3;
  });
  
  

  Or, if you don’t like the forEach command:

  for (let i = 0; i < arr.length; i++) {
    arr[i].y1 = i * 3;
  }
  
  

  If you have controls bound to the array and want them to be notified of the change, you can wrap either of these in a call to deferUpdate:

  arr.deferUpdate(() => {
    arr.forEach((item, index) => {
      item.y1 = index * 3;
    });
  });
  
  

  I hope this helps.

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  lucas.gagneten

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  Posted 30 April 2019, 10:29 am EST

  Thanks!