Alternative to if else chain with range

Question

Please check the code below

   if( x > 10 && x <= 100 ){
      do.something(1)
    }
    else if ( x > 100 && x <= 1000 ) {
      do.something(2)
    }
    else if ( x > 1000 && x <= 10000 ) {
      do.something(3)
    }
    else if ( x > 10000 && x <= 100000 ) {
      do.something(4)
    }

Is the any better alternative to this if/else or switch chain?
Can we make it configurable - so that I can keep all the conditions and corresponding action in one data-structure and write code that can pick all the conditions from that structure and do actions accordingly? This will help me keep all the conditions in a separate conf file and it will be easy to just make the edits to that and not touch the code

NOTE: These ranges may be inconsistent like 100 - 200, 345 - 956, 1000 - 1200

The conditions `x > 100` and `x > 1000` and `x > 10000` are redundant. When the code enters those paths those conditions are always true (because they are on the `else` paths of `x <= 100` and so on.) — axiac, Jul 13 '18 at 11:34
@noobs, All the answers mentioned in that answer use consistent ranges. Ranges in my case can be inconsistent! — joginder singh, Jul 13 '18 at 11:34

Nina Scholz · Accepted Answer · 2018-07-13T11:44:10.433

2

You could take an array and use the shor circuit of Array#some for a found range.

var value = 300;
    values = [
        [10, () => undefined],
        [100, () => do.something(1)],
        [1000, () => do.something(2)],
        [10000, () => do.something(3),
        [100000, () => do.something(4)]
    ];

values.some(([v, f]) => {
    if (value <= v) {
        f();
        return true;
    }
});

edited Jul 13 '18 at 11:44

answered Jul 13 '18 at 11:13

Nina Scholz

376,160
25
347
392

I want it to be configurable and do not want the if chain – joginder singh Jul 13 '18 at 11:36
This doesn't have the `if/else` chain. It tests the value you pass against the contents of an array, and if it finds a match, it calls a function. – mccambridge Jul 13 '18 at 14:50

score 0 · Answer 2 · answered Jul 13 '18 at 11:21

This would make it configurable.

const cond = [
  {min: 10, max: 100, val: 1},
  {min: 100, max: 1000, val: 2},
  {min: 1000, max: 10000, val: 3},
  {min: 10000, max: 100000, val: 4},
]

do.something(cond.filter(c => x > c['min'] && x < c['max'])[0]['val'])

score -1 · Answer 3 · answered Jul 13 '18 at 11:09

-1

I think it is fastest way, but not for IE check here
Yes, you can write it for example in .json or .env file, and read it.

answered Jul 13 '18 at 11:09

Michał Tkaczyk

732
5
18

Alternative to if else chain with range

3 Answers3