cljs.math/expm1

functionsince v1.11.50Edit
(expm1 x)

Source docstring:
Returns e^x - 1. Near 0, expm1(x)+1 is more accurate to e^x than exp(x).
If x is ##NaN => ##NaN
If x is ##Inf => #Inf
If x is ##-Inf => -1.0
If x is zero => x
See: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/expm1
Source code @ clojurescript:src/main/cljs/cljs/math.cljs
(defn ^number expm1
  {:added "1.11.10"}
  [x] (Math/expm1 x))