optimization - javascript growth optimisation -

i need more efficient way increment value 0.0001 every 1 in parsed number. code quoted below won't cause browser crash if enter large number.

function example(amm) {      var base = 1;      var ret = 0;      	      for(var i=1; i<=amm; i++) {      	base += 0.0001;          ret += base;      }      return [base,ret];  };    var total = example(100);  console.log(total[0].tofixed(4));  console.log(total[1].tofixed(4));

update: need ret , base returned

after analysis, function can reduced this:

function example(amm) {    var base = 1 + amm*0.0001;    var ret = amm + 0.0001 * (amm)*(amm + 1)/2;    return [base.tofixed(4), ret.tofixed(4)];  }  console.log(example(100));  console.log(example(200));  console.log(example(1000));  console.log(example(2000));

why?

base = 1 ret = 0 for(var i=1; i<=amm; i++) {         base += 0.0001;         ret += base; } now, above just:     base = 1 + amm*0.0001 // sums 0.0001 amm times , has initial value of 1     ret = 1 + (1.0001) + (2.0002) + (3.0003) + (4.0004) + ... + (amm + 0.0001*amm)         = 1*amm + 0.0001*((amm)*(amm + 1)/2)         = amm + 0.0001*((amm)*(amm + 1)/2) 

some tests:

function example1(amm) {    var base = 1;    var ret = 0;    for(var i=1; i<=amm; i++) {      base += 0.0001;      ret += base;  	}    return [base.tofixed(4), ret.tofixed(4)];  }  function example2(amm) {    var base = 1 + amm*0.0001;    var ret = amm + 0.0001 * (amm)*(amm + 1)/2;    return [base.tofixed(4), ret.tofixed(4)];  }  console.log(example1(100) + ' === ' + example2(100));  console.log(example1(1564) + ' === ' + example2(1564));  console.log(example1(21343) + ' === ' + example2(21343));  console.log(example1(132) + ' === ' + example2(132));  console.log(example1(0) + ' === ' + example2(0));  console.log(example1(1) + ' === ' + example2(1));