How to create array name from function parameter

Question

I want to create an array from a function. How would I go about doing this so that the array name is passed within the parameter.

function arrayCreate(name){
     name = [];
    }

So if I used arrayCreate("Hello") I would have Hello = [] as an array. The obvious problem is I'm passing a string so how would I overcome this.

To explain a bit more about my problem I have a function which updates a chart as seen below:

      self.updateChart = function(name){

        if (typeof chartData == 'undefined') {
          chartData = [];
        }
        chartData.push({
          date: game.tickCount,
          visits: self.price,
        });
        priceLabour.validateData();
        return chartData;
        }

Now the "chartData = []" and "priceLabour" I would like for it to be dynamic and change based on the "name" parameter.

I want to display different charts which require different named arrays — epayne, Feb 20 '17 at 16:23
I have an Object called Market.list which to create a graph I use Market.list[4].updateChart();. Obviously it's fine for one market but I want to re-use the code — epayne, Feb 20 '17 at 16:27
It doesn't look like it should matter what the array is named since it's only being referenced inside this function. Why do you need to specify a name? — shanzilla, Feb 20 '17 at 16:29
Because for amChart it takes in a dataProvider called chartData. I want to use the same chart but I can't use chartData array again — epayne, Feb 20 '17 at 16:33
Can you provide a code example of where else you need to use the chartData array? I'm still not seeing why you need to pass in a name. — shanzilla, Feb 20 '17 at 16:35
I'm using this library https://www.amcharts.com/demos/line-chart-with-scroll-and-zoom/ if you click on the source code you can see "chartData" — epayne, Feb 20 '17 at 16:38

score 1 · Answer 1 · answered Feb 20 '17 at 16:17

1

You can't just create variables by a string. You can create, assign, and read properties on objects using a string:

var obj = {};
obj[name] = [];
obj[name].push(...);

answered Feb 20 '17 at 16:17

Daniel A. White

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So there's no way I can change the edited code I just added? – epayne Feb 20 '17 at 16:29
@epayne not that i can tell. seems to be a leaky global however. – Daniel A. White Feb 20 '17 at 16:30
I declared chartData = []; outside the function – epayne Feb 20 '17 at 16:36

score 0 · Answer 2 · answered Feb 20 '17 at 17:06

You can create a dynamically named array as a property of an object. Not entirely sure what your needs are but here's an example based on your provided code.

  var data = {};

  self.updateChart = function(name){
    // Store a shallow clone of the chartData array in the data obj
    data[name] = chartData.slice(0);

    if (typeof data[name] == 'undefined') {
      data[name] = [];
    }
    data[name].push({
      date: game.tickCount,
      visits: self.price,
    });
    priceLabour.validateData();
    return data[name];
  };

After calling updateChart you should be able to use data["myString"] elsewhere to refer to your array.

How to create array name from function parameter

2 Answers2