Use the ifelse statement to handle combinations of multiple variables

Question

I have two variables as follows:

var a = "active" //[Two possible values ​​active/inactive]
var b = "inactive" //[Three possible values ​​active/locked/disabled]
var outcome = ""

    if(a=="active" && b=="active")
      outcome = "a";
    elif(a=="active" && b=="locked")
      outcome = "b"
    elif(a=="active" && b=="disabled")
      outcome = "c"
    elif(a=="inactive" && b=="active")
      outcome = "d"
    elif(a=="inactive" && b=="disabled")
      outcome = "e"
    elif(a=="inactive" && b=="locked")
      outcome = "f"

In JS, besides using ifelse to check different conditions, what is the most efficient way to describe possible outcomes? Please provide suggestions.

Answer 1

You can make your logic more data-driven by using objects, for example:

var outcomeMap = {
  active: {
    active: "a",
    locked: "b",
    disabled: "c"
  },
  inactive: {
    active: "d",
    locked: "e",
    disabled: "f",
  }
};

You can then set your outcome variable by accessing that object using a and accessing the value of the nested object, for example:

var outcome = outcomeMap[a][b];

Please note that if a can be any other value than the one you mentioned, it is better to check outcomeMap[a] before accessing b Whether it is undefined. This can be done using optional chaining if your environment supports it, for example: outcomeMap[a]?.[b];

Alternatively, you can set up an array containing the possible combinations and then loop through them to check if your combination matches. Then, based on the current index, if a result is found, you can index to your result (outcomes), for example:

function getOutcome(a, b) {
  const aVals = ['active', 'inactive'];
  const bVals = ['active', 'locked', 'disabled'];
  const outcomes = [['a', 'b', 'c'], ['d', 'e', 'f']];

  for(const [i, aVal] of aVals.entries()) {
    for(const [j, bVal] of bVals.entries()) {
      if (aVal == a && bVal == b) {
        return outcomes[i][j];
      }
    }
  }
  // return ''; if you want a default value of empty string
}
const outcome = getOutcome('inactive','locked');
console.log(outcome);

Please note that neither method is more efficient than using an if statement. However, if you have more possibilities, they should be easier to scale.