Adding custom option to Value Setter (user input)

The value setter is a powerful tool that allows us, calculatorians, to hide the true values of variables behind understandable words. However, this reduces flexibility and limits the options for input 1.

There is a way to keep the flexibility for those users that want mo powa babeh, without sacrificing the experience of those users that want the simplest possible calculator.

You can include a Custom or Select your own option in your value setter and set a condition inside onResult context so that the variables affected by that value setter will be shown as the user selects that option.

We will use the same example as in the Value Setter Basics section with the different stars. This time the user will have the option to select his own parameters and (warning: marketing BS ahead) effectively creating their own star!

See also

We have created a calculator using this code so that you can see the results for yourself. Check it out at Value Setter (Custom Option) on BB.

Here is the code needed to create said behaviour:

 1'use strict';
 2
 3omni.onInit(function(ctx) {
 4    omni.createValueSetter('star', starVS);
 5    ctx.setDefault('star', 200);
 6});
 7
 8omni.onResult([], function(ctx) {
 9    ctx.hideVariables('m_star', 'r_star', 'distance');
10    if (!ctx.getNumberValue('star')) {
11        ctx.showVariables('m_star', 'r_star', 'distance');
12    }
13    ctx.addTextInfo("The value of 'm_star' is: " + ctx.getNumberValue('m_star'));
14    ctx.addTextInfo("The value of 'r_star' is: " + ctx.getNumberValue('r_star'));
15    ctx.addTextInfo("The value of 'distance' is: " + ctx.getNumberValue('distance'));
16});
17
18var starVS = [
19    {"name": "51 Pegasi", "uid": "200", "values": {"m_star": 2.20779E+30, "r_star": 860580900.0, "distance": 4.73035E+17}},
20    {"name": "Kepler 452", "uid": "201", "values": {"m_star": 2.06259E+30, "r_star": 772227000.0, "distance": 1.73131E+19}},
21    {"name": "Kepler 442b", "uid": "202", "values": {"m_star": 1.23318E+30, "r_star": 417420000.0, "distance": 1.14096E+19}},
22    {"name": "Kepler 62", "uid": "203", "values": {"m_star": 1.37241E+30, "r_star": 445248000.0, "distance": 9.36609E+18}},
23    {"name": "GSC 02620-00648 ( TrES-4)", "uid": "204", "values": {"m_star": 2.34702E+30, "r_star": 1252260000.0, "distance": 1.77015E+21}},
24    {"name": "Kepler-1520", "uid": "205", "values": {"m_star": 1.51164E+30, "r_star": 493947000.0, "distance": 2.17596E+19}},
25    {"name": "HR2562", "uid": "206", "values": {"m_star": 2.5857E+30, "r_star": 832613760.0, "distance": 1.03771E+18}},
26    {"name": "Gliese 436", "uid": "207", "values": {"m_star": 8.1549E+29, "r_star": 292194000.0, "distance": 3.0085E+17}},
27    {"name": "PSR B1257+12", "uid": "208", "values": {"m_star": 2.7846E+30, "r_star": 973980000.0, "distance": 2.1911E+19}},
28    {"name": "Proxima Centauri", "uid": "209", "values": {"m_star": 2.42857E+29, "r_star": 107276940.0, "distance": 3.97349E+16}},
29    {"name": "Gamma Cephei", "uid": "210", "values": {"m_star": 2.80449E+30, "r_star": 3429801000.0, "distance": 4.25732E+17}},
30    {"name": "Sun", "uid": "211", "values": {"m_star": 1.989E+30, "r_star": 695700000.0}},
31    {"name": "Enter your own", "uid": "0", "values": {}},
32];

As you can see, the only necessary steps are to create a new entry with a different uid and no values attached. This last part is crucial since it allows the user to input any number anywhere without the selection in the value setter changing.

Note

Once again we have used the trick of defining the special behaviour under uid = 0 so that the condition inside the if on line 10 is as simple as possible.

Because the custom option has no values assigned to it and the actual variables are no shown unless the user selects Enter your own we are guaranteed that the value setter will never fall into an undefined uid.

Footnotes

1

Unless you have infinite time and resources in which case, can you please help me? ^^