Add support for logarithmic functions

- log(x): base 10 - ln(x): base e
heokhe · Apr 2, 2021 · 58c6e6d · 58c6e6d
1 parent 58d8bcc
commit 58c6e6d
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diff --git a/lib/functions/index.js b/lib/functions/index.js
@@ -3,6 +3,8 @@ const trigonometric = require('./trigonometric');
 
 module.exports = {
   ...trigonometric,
+  ln: Math.log,
+  log: Math.log10,
   cbrt: Math.cbrt,
   sqrt: Math.sqrt,
   abs: Math.abs,

diff --git a/tests/calc.test.js b/tests/calc.test.js
@@ -41,3 +41,8 @@ tap.equals(evalExpression('cos(270)'), 0);
 
 // trigonometric functions: tan & cot
 tap.equals(evalExpression('cot(4)'), 1 / evalExpression('tan(4)'));
+
+// logarithmic functions
+tap.equals(evalExpression('log(100)'), 2);
+tap.equals(evalExpression('ln(1)'), 0);
+tap.equals(evalExpression('log(64) / log(8)'), 2);