fix: #3323 support functions in function clone

AUTHORS

@@ -255,5 +255,6 @@ Brooks Smith <42363318+smith120bh@users.noreply.github.com>
 Jmar L. Pineda <63294460+Galm007@users.noreply.github.com>
 gauravchawhan <117282267+gauravchawhan@users.noreply.github.com>
 Neeraj Kumawat <42885320+nkumawat34@users.noreply.github.com>
+Emmanuel Ferdman <emmanuelferdman@gmail.com>
 
 # Generated by tools/update-authors.js

src/utils/object.js

@@ -40,6 +40,11 @@ export function clone (x) {
     return mapObject(x, clone)
   }
 
+  if (type === 'function') {
+    // we assume that the function is immutable
+    return x
+  }
+
   throw new TypeError(`Cannot clone: unknown type of value (value: ${x})`)
 }
 

test/unit-tests/function/utils/clone.test.js

@@ -88,6 +88,13 @@ describe('clone', function () {
     assert.strictEqual(b.valueOf()[2].re, 2)
   })
 
+  it('should clone a function', function () {
+    const f = () => 42
+    const a = math.matrix([f])
+    const b = math.clone(a)
+    assert.strictEqual(b.get([0]), f)
+  })
+
   it('should LaTeX clone', function () {
     const expression = math.parse('clone(1)')
     assert.strictEqual(expression.toTex(), '\\mathrm{clone}\\left(1\\right)')

test/unit-tests/utils/object.test.js

@@ -84,7 +84,6 @@ describe('object', function () {
 
     it('should throw an error in case of an unsupported type', function () {
       assert.throws(function () { clone(/a regexp/) }, /Cannot clone: unknown type of value/)
-      assert.throws(function () { clone(() => 42) }, /Cannot clone: unknown type of value/)
     })
   })