fixes and refactoring

1 files changed, 12 insertions, 1 deletions

diff --git a/src/gleam_stdlib.mjs b/src/gleam_stdlib.mjs
index 59077e9..6604bff 100644
--- a/src/gleam_stdlib.mjs
+++ b/src/gleam_stdlib.mjs
@@ -247,7 +247,18 @@ export function power(base, exponent) {
 }
 
 export function random_uniform() {
-  return Math.random();
+	let random_uniform_result = Math.random();
+	// With round-to-nearest-even behavior, the ranges claimed for the functions below
+  // (excluding the one for Math.random() itself) aren't exact.
+  // If extremely large bounds are chosen (2^53 or higher),
+  // it's possible in extremely rare cases to calculate the usually-excluded upper bound.
+  // Note that as numbers in JavaScript are IEEE 754 floating point numbers
+  // See: <https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/random>
+	// Because of this, we just loop 'until' we get a valid result where 0.0 <= x < 1.0:
+	if (random_uniform_result === 1.0) {
+		return random_uniform();
+	}
+  return random_uniform_result;
 }
 
 export function bit_string_slice(bits, position, length) {