CODEWITHSUNDEEP
javascript
user1234
user1234

Reputation: 3159

How to add a property to all the objects in an array and set its value dynamically.-Javascript

I have an array of objects and I want to add a prop of type Object to every object, just that the value of the field will be dynamic.

var data= [
              { name:"Jan", y:0 },
              { name:"Feb", y: 71.5 },
              { name: "Mar", y:106.4 },
              { name: "Apr", y:106.4 },
              { name: "May", y:0 },
              { name: "Jun", y:106.4 },
              { name: "Jul", y:166.4 },
              { name: "Aug", y:36.4 },
              { name: "Sep", y:0 },
              { name: "Oct", y:26.4 },
              { name: "Nov", y:206.4 },
              { name: "Dec", y:92.4 }
            ]

now I want to add a prop to it. //added prop to the first item in the array.

data[0].plot = {rad: 1}

My issue is: 1) how can I add the "plot" object to every single item in the data 2) the value of rad should be such a way that it should correspond to the value of 'y' in the data i.e: if value of 'y' =0,(its min value in the data) then the "rad" value should be 1, similarly: value of y=206.4(its max value), then rad should be 10.

The "rad" values in between 0 and 206.4 should correspond to the values of 'y' and fall between 1-10 (this is the "rad" range).

I hope this makes sense. I'll clarify with details if needed, Thanks in advance!!

Upvotes: 0

Views: 45

Answers (1)

Josh Beam
Josh Beam

Reputation: 19772

You can do something like this (check out the jsbin):

data.forEach(datum => {
  datum.plot = {
    rad: (10 * datum.y)/206.4 || 1
  }
})

I think that's the right formula for converting your y to rad... Anyway, the principle is that you can just loop through objects and attach the property to each one dynamically. Aside from the programming aspect, you'll just need to figure out whatever the correct math formula is, and then put it in there to calculate whatever value you need.

Upvotes: 3

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