Declarative vs Imperative

DeclarativeVsImperative.js

// Not sure this is accruate, but I was wondering about different styles.
(function(){
    
    let sum = e=>e+1;
    let sub = e=>e-1;
    let mul = e=>e*e;
    let div = e=>1/e;
    let dataSet = [1,2,3];
    let dataSet2 = [4,5,6];
    
    // Imperative 
    // console.log(dataSet.map(sum)); // Do thing
    // console.log(dataSet.map(sub)); // Do thing
    // console.log(dataSet.map(mul)); // Do thing
    // console.log(dataSet.map(div)); // Do thing

    // Functional?
    let actionProcessor = data => e=>console.log(data.map(e)); // Declare thing to do and what to do it on.
    let applyFun = dataSet => [sum,sub,mul,div].forEach(actionProcessor(dataSet));
    // [dataSet,dataSet2].forEach(applyFun); // Do thing

    //Declarative
    let actionObj = {
        actions:[sum,sub,mul,div], // Default, Declare thing to do when set.
        set runData(value){
            this.actions.forEach(action=>console.log(value.map(action)))
        }
    };
    actionObj.actions=[sum,sub,mul,div];
    actionObj.runData=dataSet; // Set data.
    actionObj.actions=[sum,sub];
    actionObj.runData=dataSet2; // Set data.

})();