| 1 | /**
|
| 2 | * Compares two BigNumbers.
|
| 3 | * @param {BigNumber} x First value to compare
|
| 4 | * @param {BigNumber} y Second value to compare
|
| 5 | * @param {number} [epsilon] The maximum relative difference between x and y
|
| 6 | * If epsilon is undefined or null, the function will
|
| 7 | * test whether x and y are exactly equal.
|
| 8 | * @return {boolean} whether the two numbers are nearly equal
|
| 9 | */
|
| 10 | export function nearlyEqual (x, y, epsilon) {
|
| 11 | // if epsilon is null or undefined, test whether x and y are exactly equal
|
| 12 | if (epsilon === null || epsilon === undefined) {
|
| 13 | return x.eq(y)
|
| 14 | }
|
| 15 |
|
| 16 | // use "==" operator, handles infinities
|
| 17 | if (x.eq(y)) {
|
| 18 | return true
|
| 19 | }
|
| 20 |
|
| 21 | // NaN
|
| 22 | if (x.isNaN() || y.isNaN()) {
|
| 23 | return false
|
| 24 | }
|
| 25 |
|
| 26 | // at this point x and y should be finite
|
| 27 | if (x.isFinite() && y.isFinite()) {
|
| 28 | // check numbers are very close, needed when comparing numbers near zero
|
| 29 | const diff = x.minus(y).abs()
|
| 30 | if (diff.isZero()) {
|
| 31 | return true
|
| 32 | } else {
|
| 33 | // use relative error
|
| 34 | const max = x.constructor.max(x.abs(), y.abs())
|
| 35 | return diff.lte(max.times(epsilon))
|
| 36 | }
|
| 37 | }
|
| 38 |
|
| 39 | // Infinite and Number or negative Infinite and positive Infinite cases
|
| 40 | return false
|
| 41 | }
|