added exp

README.md

@@ -114,6 +114,20 @@ divide("-714.7008086132632", "8135.725531"); // -714.7008086132632 / 8135.725531
 '-0.0878472123832102762218908980055167989417759034280282678823325216230183564682007707223868489179001533'
 ```
 
+### exp
+Raise [Euler's Number](https://en.wikipedia.org/wiki/E_(mathematical_constant)) to the given power
+```js
+import exp from "preciso/exp.js";
+
+exp("-Infinity") // "0"
+exp("-1") // "0.3678794411714423..."
+exp("0") // "1"
+exp("1") // "2.718281828459045..."
+exp("2") // "7.389056098930650..."
+exp("10") // "22026.46579480671..."
+exp("Infinity") // "Infinity"
+```
+
 ### factorial
 ```js
 import factorial from "preciso/factorial.js";

exp.js

@@ -0,0 +1,21 @@
+const clean = require("./clean.js");
+const is_negative_infinity = require("./is_negative_infinity.js");
+const is_positive_infinity = require("./is_positive_infinity.js");
+const is_zero = require("./is_zero.js");
+const eulers_number = require("./eulers_number.js");
+const pow = require("./pow.js");
+
+function exp(power, { max_decimal_digits } = {}) {
+  const e = eulers_number(100);
+
+  if (is_negative_infinity(power)) return "0";
+  if (is_positive_infinity(power)) return "Infinity";
+  if (is_zero(power)) return "1";
+
+  power = clean(power);
+
+  return pow(e, power, { max_decimal_digits });
+}
+
+module.exports = exp;
+module.exports.default = exp;