How to use Map array function within object constructor

Question

How can I use map function to have 3 arrays under datasets instead of another object called 'label'. When I try to put map function before 'label', just after 'dataset' in constructor function I am getting weird errors about having unexpected '.' dots etc.

Expected output

{
  colors: blue,
  datasets: [
    {
      label: 'car',
      type: 'line',
      data: '1'
    },
    {
      label: 'bus',
      type: 'line',
      data: '5'
    },
    {
      label: 'train',
      type: 'line',
      data: '10'
    }
  ]
}

function Constructor(colors, label, type, data) {
  this.colors = colors;
  this.label = label;
  this.type = type;
  this.data = data;

  this.mainData = {
    colors: colors,
    datasets: [{
      label: label.map((label, i) => ({
        type: type,
        data: data[i]
      }))
    }]
  }
};

var whyYouNoWork = new Constructor('blue', ['car', 'bus', 'train'], 'line', ['1', '5', '10']);

console.log(whyYouNoWork.mainData);

Ele · Accepted Answer · 2018-03-22 15:18:38Z

2

You can use the function map to build the desired output:

function Constructor(colors, label, type, data) {
  this.colors = colors;
  this.label = label;
  this.type = type;
  this.data = data;

  this.mainData = { colors, datasets: label.map((label, i) => ( { label, type, data: data[i] } ) ) }
};

var whyYouNoWork = new Constructor('blue', ['car', 'bus', 'train'], 'line', ['1', '5', '10']);

console.log(whyYouNoWork.mainData);

.as-console-wrapper { max-height: 100% !important; top: 0; }

answered Mar 22, 2018 at 15:18

Ele

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1 Comment

lovemyjob Over a year ago

why do I have to get rid of [{ after datasets: ?

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