broken toFixed implementation

Question

The default implementation of javascript\'s \"Number.toFixed\" appears to be a bit broken.

console.log((8.555).toFixed(2));    // returns 8.56
console.log((         


        

Answer 1

A consistent solution would be to add a fixed tolerance (epsilon) to each number before rounding. It should be small, but not too small.

For example, with an eps = 1e-9, this:

console.log((8.555).toFixed(2));    // returns 8.56
console.log((8.565).toFixed(2));    // returns 8.57
console.log((8.575).toFixed(2));    // returns 8.57
console.log((8.585).toFixed(2));    // returns 8.59

Becomes this:

console.log((8.555 + eps).toFixed(2));    // returns 8.56
console.log((8.565 + eps).toFixed(2));    // returns 8.57
console.log((8.575 + eps).toFixed(2));    // returns 8.58
console.log((8.585 + eps).toFixed(2));    // returns 8.59