Find element in array that complies to multiple conditions

JavaScript
1

Hello,

How do I find the first boiler that responds to the following conditions:
h_cap >= req_h_cap AND
ww_cap >= req_ww_cap

const boilers = [
{CW:1, ww_cap: 0, h_cap: 12, boiler_costs: 2200},
{CW:2, ww_cap: 0, h_cap: 15, boiler_costs: 2400},
{CW:3, ww_cap: 18, h_cap: 20, boiler_costs: 2600},
{CW:4, ww_cap: 22, h_cap: 24, boiler_costs: 2800},
{CW:5, ww_cap: 28, h_cap: 32, boiler_costs: 3000},
{CW:6, ww_cap: 38, h_cap: 32, boiler_costs: 3200},
] ;

Kind regards and many thanks

2

Assuming the req_ should be some kind of value coming from users choice

const matchList = boilers.Filter( b => b.h_cap > req_h_cap &6 b.ww_cap > req_ww_cap);
If(matchList.length)
    return matchList[0];
3

Thanks Thallius!

How would you change the formula, if you are only interested in the CW value of the first boiler in the array that matches both conditions?

Kind regards

5

Here is how I would find them. With your array of boilers, I would also have an array of conditions.

const conditions = [
  (boiler, requirements) => boiler.ww_cap >= requirements.req_ww_cap,
  (boiler, requirements) => boiler.h_cap >= requirements.req_h_cap,
];

Then I would check for the first boiler that matches all of the conditions.

  const found = boilers.find(function (boiler) {
    return conditions.every(function (condition) {
      return condition(boiler, requirements);
    });
  });

You can see some example code of that at https://jsfiddle.net/5vc1p8Lu/

Or, if you want to use arrow notation:

  const found = boilers.find(
    (boiler) => conditions.every(
      (condition) => condition(boiler, requirements)
    )
  );
1 Like
6

To be honest for me this is an example where the new way of „clean code“ is going a step too far.

I find your code much harder to read then just using a and condition in the find itself

const found = boilers.find(
    (boiler) => boiler.ww_cap >= requirements.req_ww_cap && 
                boiler.h_cap >= requirements.req_h_cap
    )
  );
1 Like
7

I agree, using the conditions directly inline does result in easier to understand code.
I am guilty of premature optimisation.

Later on if a wider range of conditions were needed, or if the number of requirements were wanting to be changed, then extracting them out to an array would be appropriate.

2 Likes
8

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